Door to Before

""I have noticed some consistancies with all the Half-Life games: you always have to go through incredible odds of alien monsters and potent deathtraps and evil soldiers and treacherous jumps and taxing challenges just to get to the other side of a locked wooden door.""

- Thomas Savage, in the notes for Concerned #172

""Oh my god, this is where I just came from! Am I going in circles?""

- Gordon Freeman, Freemans Mind

So, you've hacked and slashed your way through a dungeon and possibly passed a Point of No Return or two. You have reached the final room and taken the MacGuffin, and are now ready to leave this place.

The only question is... how? There's no way the game designers will make you backtrack through all the corridors you've cleansed all the way to the entrance, right? And sometimes, it may even be impossible, as the original route has been blocked.

Luckily, there's a conveniently placed door, right there in the final room, just waiting for you to open it. You go through it and, voila, you're at the entrance, right where you started, saving you the trouble of returning here the long way.

More often than not, you may even recognize the door as a Locked Door from before, which would be very convenient if you had a way to open it from the other side before you went the long route, saving you all the trouble. Of course, it's initially always impossible even with a BFG in your arsenal, but once you easily open the door from the other side, it will usually remain open, giving you quick access to the area that once used to be so hard to reach.

Particularly asinine game designers may even replace a locked door with an Insurmountable Waist Height Fence that's just too high to climb from one side, but once you reach its other side, there's something that allows you to climb and jump it and thus have a shortcut to a previously explored area.

Of course, search-and-rescue missions will never have such convenient shortcuts -- instead, the player will have to bring the rescued prisoners all the way to the original entrance... and the corridors that you already fought your way through once will probably be repopulated with Respawning Enemies.

If you utillize your newfound MacGuffin to create a new exit, it counts as a Metroidvania.

These are a favorite of Speedrunners, as it's quite common for games to have glitches that make it possible to open the one-way doors from the wrong way, skipping minutes to hours of gameplay.

Note: non-Video Game examples go at the end.

Video Games

 * ICO is an entire Door to Before moment. It starts out deep within a castle's catacombs, then works its way into an Escort Mission that takes Ico and Yorda through a game-long flight across a full-scale island fortress. They navigate inconveniently gaping chasms, death-rigged rooms, tedious puzzle-based chambers and basically tour the whole building - ramparts, gardens, cemeteries - to unlock the one escape door. When you finally open the doors,  , so you have to climb your way back to where you started out at the catacombs for one last fight.
 * In the old server complex in The Nameless Mod, there is a door that is just out of reach. When you go through the entire level, it is the door that will take you back to the entrance.
 * The original Half-Life is ridden with both "door" and "fence" varieties. Usually, once you get to the other side, you have to press a button or remove a bar to unlock it.
 * Half-Life 2 has at least a couple doors that are blocked because there's a couch or something keeping them from opening. When you get to the other side, you can gravity-punt it out of the way.
 * The most blatant comes early in the original, where you fight many soldiers and go outside just because one security guard who could have opened a door didn't think to grab a shotgun while being attacked. Oh, and there is a scientist near this shotgun who could've helped, or at least pushed a button while his buddy scientist screamed at him to do it.
 * This concept is referred to as a "loop" in game design, at least by Valve. This section of the Valve Developer Community (a wiki for using Source's Hammer level editor) explains the reasons for using them, and advantages/disadvantages of their use. Link.
 * The training level in Nox. The ogre village level is an odd example of a search-and-rescue mission that does have a Door to Before -- namely, the front gate that can only be opened from the inside.
 * Numerous examples in Killer7.
 * Milons Secret Castle has this in each of the accessible rooms from outside the castle. The only difference is that you actually have to find the door by blasting a bubble at its location, and then find its key.
 * Dragon Quest Heroes Rocket Slime has one of these back to Boingburg every time you beat one of the major bosses.
 * In Breath of Fire III
 * The entrance to the Vulkar base in Knights of the Old Republic, requiring the player to seek an alternate way through the rakghoul-infested Undercity sewers.
 * The exit from Ludo Kressh's tomb in the sequel, although it isn't visible from the other side.
 * A good number of Zelda games have made use of this, which happens when Link grabs the Triforce piece, instrument, or whatever other quest item he beat the dungeon's boss to get.
 * The Legend of Zelda a Link To T He Past did not: Beating the boss transported you to the dungeon exit, but returning to the boss' room later can leave you stranded, forcing you to use the "teleport me back" magic item (or save and exit).
 * it's implied that link walks out of the lightworld dungeons, as the door opens when you grab the pendant. he instead uses the mirror in the dark world because the doors stay closed when he grabs the crystals.
 * The Legend of Zelda Ocarina of Time and later games have Link entering a portal of light that opens up in the ground after beating a boss.
 * Ocarina also gave you Farore's Wind, which was a sort of reversal of this, as casting it created a waypoint for whatever room of the dungeon you were in. Because saving and quitting returned you to the entrance, this was an easy way to pick up where you left off.
 * Also, many of the boss chambers were accessed from a room fairly close to the entrance: much of the level revolved around acquiring either the key or the MacGuffin that allowed you access to the boss chamber.
 * Starting with The Legend of Zelda the Wind Waker, the series has included enormous dungeons with a number of teleport-out exits. But watch out, since those exits are one-way, that means another trek through dozens of rooms of freshly repopulated dungeon.
 * It also applies to the overworld map in The Legend of Zelda the Minish Cap: picking up certain items or approaching from the other side allows one to open up shortcuts that bypass challenging enemies and puzzles.
 * In The Legend of Zelda Twilight Princess, you can locate a creepy birdlike creature called Ooccoo in most of the dungeons, and rescue her from the pot in which she's managed to trap herself. After that you carry her around like an item for the duration of your time in the dungeon, and can use her at any time to be immediately transported to the dungeon exit. This is in addition to Midna teleporting you out after you've defeated the dungeon boss.
 * You can use Ooccoo's even creepier son to teleport back to the room you used Ooccoo in, which means that you don't have to traipse all the way back through the dungeon.
 * In Zelda II the Adventure of Link, the 6 palaces have a back door just past the statues you place the crystals in that takes you outside. It makes one wonder why Link doesn't just use these doors to begin with and skip the whole dungeon...
 * The Legend of Zelda Skyward Sword is full of these.
 * City of Heroes takes it a step further: If you successfully complete a mission, an "exit" button will appear in the compass window. Click it while anywhere in the mission interior and you somehow find yourself outside instantly, even if you were totally surrounded by hostiles a moment ago.
 * Conversely, City of Heroes follows the search-and-rescue example in the trope definition to a T. You've just slogged through anywhere from two to five floors to rescue Dr. Helpless Scientist and then have to lead them all the way back the way you came to the front door, almost invariably fighting off waves of ambushes along the way. And forget about using stealth powers to avoid detection on the way out. Your rescuee can't see you either!
 * The "stealth" portion has been fixed by an update. Rescuees can still see you when you're stealthed, but, because you're escorting someone, being stealthy is much more difficult, resulting in a massive penalty to your stealth ability. So if you invisibled yourself past all the mobs, get ready to fight them all on the way out.
 * There's a good reason why players using the Mission Architect vastly prefer to use the old "release the captive and let them find their own way out" option instead of "escort back to the entrance".
 * Used in 'The Great Cave Offensive' in Kirby Super Star: In the beginning of the game you see tiles on the floor that are different than the floor; After making it through the labyrinth, collecting treasure and defeating bosses along the way, you find a bomb block that destroys the tiles leading you back to the surface where the game started with a Warp Star ready for you.
 * The Resident Evil series just loves doors apparently only held shut by a simple latch on one side.
 * Resident Evil 0 makes more use of this trope than any of the rest in the franchise, partly because of a gameplay mechanic change: There's no Item Storage Box anymore, you just drop your weapons and items right on the ground to be picked up later. To make backtracking easier, you find tons of shortcuts to earlier parts of the game. Even near the very end, it's possible to go right to the beginning part of the mansion from a simple elevator.
 * The novelizations subvert this trope, as the characters have no compunctions about blowing open a door with a shotgun, though it does take a few shells to do so. And in the remake of Resident Evil for the Gamecube, Barry Burton does blast open a locked door during the (no-longer-dreadful) Jill Sandwich sequence, making it an example of Cutscene Power to The Max, since you can never do that yourself.
 * In Paper Mario the Thousand Year Door, the beating of a boss usually send you outside automatically, but not so with the defeat of Cortez. However, the room before the ship then has a convenient way back to the shore of Keelhaul Key, if only you can get past that newly-cracked wall...
 * Same for the first game, although convenient switches to other characters hide how exactly Mario got out, on his own or by help of the newly rescued Star Spirit.
 * With the exception of Chapter 5 (same as the Cortez example, oddly), which shows Misstar airlifting Mario and company out the top of Mt. Lavalava, Outrun the Fireball-style.
 * Found in many dungeons and caves (especially quest-related ones and Ayleid Ruins) in The Elder Scrolls IV Oblivion. Sometimes the door can be easily traversed from either side, but is hidden in such a way that you would have to be especially observant, or know exactly where to look, to bypass the level.
 * A particularly extreme example is with the Mehrune's Razor DLC. After going through a load of ruins, caves and dungeons, fighting your way through a small army plus a few other foes, you finally reach Mehrune's Razor. After taking the weapon, a secret door will open and it leads right to the outside through a hidden underwater passage. It takes about 30 seconds to leave the dungeon but it takes about an hour to get there.
 * It is ubiquitous in Skyrim dungeons as well. Barred doors, stones that slide down upon some action, doors to outdoor (and therefore Fast Travel) overlooks...
 * One way Waystones at the ends of a few dungeons in Final Fantasy XII, except without the easy return option: "By this, return ye to [wherever you came from]. By other means, return ye here."
 * Happened earlier in Final Fantasy VI; after opening the Sealed Gate, hitting Kefka, releasing a few Espers, and watching it seal back up, a one-way Door to Before appears in the anteroom to take you back to the first room.
 * Actually happened even earlier than that in Final Fantasy III with the Teleport spell, that only works in dungeons!!! Oh, except the final dungeon.
 * Also done in Final Fantasy VIII during the Galbadia Missile Base mission. Bizarrely, the door only opens if you set the self-destruct timer to twenty minutes or less; otherwise you have to backtrack.
 * In Final Fantasy X, late into the game, you gain the ability to board the airship from any save point. It's not exactly a way back to the beginning of the dungeon (you have to travel back there if the airship doesn't drop you off right in front of it), but it's a nice escape if you need to restock on supplies.
 * The Hordes of the Underdark expansion for Neverwinter Nights features a dungeon that has a locked door at the entrance. Normally this is a door to before that opens from the other side once you complete the dungeon. However, if you have a character with enough points (a lot) in lockpicking it is possible to unlock the door from the entrance and skip straight to the end of the dungeon.
 * Neverwinter Nights 2 mostly averts this: after finishing your business in a zone, you're usually offered to be teleported out if it would take too long to return "manually". It's simply assumed that you walked back the same way you arrived, just off screen. The Temple of Seasons in Arvahn is one straight example with a Door to Before, and thanks to a bug, you can just pick it with the Open Lock skill and head from the entrance straight to the MacGuffin, skipping the entire dungeon.
 * The Watcher's Keep in Baldurs Gate II: Throne Of Bhaal is a pretty straight playing of this trope.
 * Skies of Arcadia features plenty of this.
 * The ruin stages of Lost in Blue and its sequel both have this feature.
 * La-Mulana had something like this in the Hell Temple: However, the player hasn't reached the goal at this point, and if they use it, they'll have to go all the way back through the temple again. (The game really does not want you to get to the end.)
 * The Metroid games absolutely THRIVE on this trope. In the Prime sub-series, especially, it's common for players to traverse the same area 4 or 5 different times, with new paths to/from it available to them each time.
 * Example: In Super Metroid, the escape sequence takes you behind Mother Brain's room and through the rest of Tourian as it's exploding, then give you a nice flat path to run down and inadvertently charge up your speed booster. Then they put some speed booster blocks in your way, which you charge through without knowing it--leading you right back to . No, you can't shinespark your way through these blocks from the right; it's literally impossible without cheating.
 * Another random example in Echoes - After going up an elevator in the Ing Hive and transporting back to Sanctuary Fortress you go through this dynamo area, which you can save at (thank god). You continue onward to the temple, then backtrack slightly and go a different way. Then you fight the Spider Guardian, and once you've beaten it, you find there is another exit at the top of the battle arena, which leads to a morph ball tube which suddenly ends and drops you - right back at the room just after that first elevator. And you don't have to use the portals to get back either, as you have the Spider Ball, which the lack of made you go into Dark Aether in the first place!
 * The Pokémon games have those ubiquitous ledges. You can hop down them, but not up, and they're often used as one-way shortcuts. Also, the one-way teleporter on the 7th gym in Pokémon Ruby and Sapphire/Emerald'', Tate and Lisa's gym. After a rather annoying puzzle where you have to ride one-way floor panels and flip switches to get to the gym leaders, they leave you a teleporter pad that leads to the front. A similar thing happens in Sabrina's gym, but it is full of teleport pads - and the only different one in Sabrina's chamber leads back to the gym's entrance.
 * Also, in Pokémon HeartGold and SoulSilver, defeating or catching Mewtwo in Cerulean Cave reveals a ladder behind Mewtwo, which leads to an island on the first floor behind one of the aforementioned ledges, not too far from the entrance.
 * In weirder example, one doorway in the deepest part of the Seafloor Cavern inexplicable takes you out to the entrance room out a door which the first one isn't connected to except when you're going that one way.
 * The Deadmines in World of Warcraft are a weird example. Even though you enter them through a house in the town of Moonbrook and keep going downwards all the way through, the one-way exit from the final cave takes you to a hill above Moonbrook.
 * Several Instances in World of Warcraft (Well, most of the Burning Crusade instances) have shortcut exits after the final boss, sometimes leading to an exit portal (Botanica, Deadmines), others lead to shortcuts leading back to the entrance portals (Blood Furnace, Underbog)
 * Now totally bypassed by the new Looking For Group functionality which will teleport you into an instance, and then return you when finished no matter where you are.
 * A number of the newer dungeons, and being refitting in some of the larger old dungeons, have portals available so that if you get killed in one of the latter parts of the dungeon and have to reenter the main entrance, you can at least partly teleport past all the stuff you have already cleared.
 * Tales of Symphonia offers this option in the last dungeon, provided that you don't go straight for the last boss right away. Upon reaching the last area, a bit of hunting will provide you with a key item called the Sacred Stone that allows you to warp between the entrance of the last dungeon and the area right before the final boss. Also, there are a couple dungeons that you must pass through to get into some towns, like the Meltokio Sewers. To save players the frustration of having to traverse these dungeons each and every time you need to go into those towns, the game offers a "Quick Jump" option that lets you warp between the dungeon's entrance, and the town itself. Lloyd also breaks the fourth wall at one point by asking why there isn't a Quick Jump option for a dungeon they had to go through a second time due to plot reasons.
 * Moria Gallery in Tales of Phantasia has a switch halfway through pulling which opens a staircase straight to the first level and another one at the end of the dungeon which goes straight to the previous, making a very convenient shortcut to the exit. Thankfully, both switches remain on for the whole 150 years, meaning the newly discovered parts are accessible straight away.
 * Portal sort of has this; shortly after Chell escapes being dropped into a horrible pit made of fire, she slides through a tube into a test chamber she had already completed somewhat early on in the game and must go through it again to move on.
 * Diablo 1 has these for each of the 3 latter areas, the Catacombs, the Caves, and Hell. Diablo 2 has the Waypoints which act just like this, but are explicitly magic, justifying the trope some.
 * Many levels in the Spyro the Dragon trilogy are giant circles; there's always a wall you can now smash or an elevator that can only be activated from the far side of the level.
 * Especially obvious in Year of the Dragon; not implemented that much in the first two games.
 * Insomniac Games seems to like this trope; pretty much every level in Ratchet and Clank is designed similarly. If there isn't a door, there's a teleporter.
 * There are many times in Dead Space in which one appears. It's often due to previously locked doors opening up, but the occasionally enemy breaking through the door occurs as well.
 * The Nancy Drew mystery game Danger on Deception Island had one of these underneath the lighthouse. Of course, to open it, you had to make your way through a branching underground cave.
 * Castlevania Order of Ecclesia forces you to fight a giant crab to get to the other side of a lighthouse. No explanation why you can't just go around the lighthouse.
 * Well, there is some useful stuff in the lighthouse; and if you didn't go in there you wouldn't get to rid the world of another evil monster by means of a giant friggin' elevator.
 * Symphony of the Night has a memorable instance of this trope: after exploring a large portion of the castle, you now find yourself on the far side of a wall you passed very early in the game. There is a conveniently placed cannon that you can use to blast the wall down. There is no reason or use for the cannon other than blasting down this wall.
 * In the PC game Darkstone, when you complete any one of the four-level dungeons, you actually do have to make your way back through the entire thing to the exit. This is, however, made easier by using the game's list of places visited in the dungeon; you just click on "Level Exit" and your avatar will promptly run the shortest route through the level to the stairs leading up.
 * Left 4 Dead has a Door To Before in No Mercy 3 after a crescendo for people that got yanked outside by a Smoker so that they can go through the door their team opened instead of going through the normal way all over again. The door was very glitchy and could be broken to bypass the event entirely. When the campaign got ported to Left 4 Dead 2, the door was even glitchier since any melee weapon could instantly break it. After several patches, the door no longer breaks, but Valve apparently forgot about players that use a Grenade Launcher, thus the door can still be broken if you have that weapon.
 * Vampire: The Masquerade Bloodlines has a particularly irritating example: after slogging your way through the Los Angeles sewers in search of the Nosferatu warren, you find a tunnel in the back of the Nosferatu primogen's room leading straight out into the Los Angeles mausoleum.
 * The Mario & Luigi series just love putting several sets of iron bars, walls or any other kind of Locked Doors that can only be opened from behind all over every single dungeon in the three games of the series. They usually lead to a big room with a Save Point or a health-recovering spot. This way, you don't have just a shorcut to the last room, but to basically any large area in the dungeon which is worth being searched for secrets.
 * Averted in Albion. If you aren't teleported back to the entrance once you reach the end of the dungeon, you have to walk all the way back. Thankfully, this only happens in smaller dungeons.
 * The Silent Hill games have these in spades. In SH2s hotel, to get behind the door to before, you have to first use a service elevator that requires you to leave all your items on the shelf, then to unlock it, you must use a lightbulb obtained from a tin can so you can see the lock.
 * Silent Hill takes advantage of its violation of the rules of physics and reality to have some really unnerving instances of this trope. Another example from the second game is when
 * In the first game, there's a door on the second floor of Nowhere that leads back to the first floor, with no visible descent in between. This door is required after you shut off the power.
 * Fallout 3 has quite a lot of these, but the most jarring example is in the Broken Steel DLC where after going deep into a small area just outside the Capital Wasteland, you return to the latter through a door...up a friggin' mountain, at an incredibly small niche in the rocks that you cannot get back up to after jumping off it.
 * Fallout 3 and New Vegas also allow you to "fast-travel" to any location, skipping traveling around the world - as long as you've been to said location at least once.
 * Other examples include the Dunwich Building and the Germantown Police Station in Fallout 3, and the REPCONN Headquarters in Fallout New Vegas. In some (but not all) cases, the door can be opened by picking a lock or hacking a termnal, allowing you to bypass the entire 'dungeon'.
 * Another example in Fallout New Vegas is vault 22. You have to go through four floors, unlock a door and wander through a cave to reach the computer terminal. At which point a NPC appears to fix the elevator so you can easily travel across all the floors. However if you have a high repair skill you can fix it yourself, happily take it down to the lowest level, then only go through 1 room and a corridor to get to the terminal.
 * When you need to get back to the surface of the asteroid in Alpha Prime, you go through the mining station's living quarters, only to pop out of a vent back at the beginning of the game, and thus the surface of the asteroid.
 * Just about every dungeon, even most of the sidequests, in Dragon Age: Origins has a convenient passage back to the start once you find the room with the big plot reveal/boss fight.
 * And if it's not an actual passage, it's an "Are you ready to go back?" dialogue option with the freshly rescued NPC.
 * While not usually seen 'before' due to the linear level design, many temple buildings in Titan Quest come with a backdoor or stairs that lead from the most guarded and sacred center straight to the outside.
 * The Persona series:
 * In Persona 4, the savepoint prior to a dungeon boss doubles as a teleport back to the entrance. Conversely, any time you enter a dungeon, you have the option of starting from the first floor, or going straight to the last floor you reached.
 * Persona 3 has the warp points that let you teleport to any other one, including the one conveniently located at the entrance.
 * The hidden tombs in Assassin's Creed II contain elaborate, time-consuming jumping puzzles. The final room of each tomb contains a convenient door leading directly outside.
 * Although, in Revelations we never see any doors/passages inside the final chamber. This makes it unlear how Ezio manages to escape, having on at least one occasion destroyed the way in.
 * The Coastal Thailand levels in Tomb Raider: Underworld feature this. You exit the final sub-ruin through an underwater tunnel with a pair of stone doors at the end - that comes out into the sea just a few metres from where you started the level set.
 * The Tomb Raider series in general is made of this trope. If some long and convoluted puzzle room doesn't finish by dropping you right back at the start of the level with MacGuffin safely in hand, usually from a ledge you didn't even notice the first time, then the level designers were asleep.
 * Borderlands does this constantly with ledges that you can jump off of, but not climb up to. Finished all the quests in a dungeon? Just look for the 8 foot ledge you can drop from to be back at the starting point.
 * In a stroke of mercy (instead of annoyance), Demons Souls is designed with shortcuts you can activate at various points through the level so you can return to your corpse after your recent and inevitable death. Its Spiritual Successor Dark Souls continues this practice.
 * Asherons Call always has portals to the surface at the bottom of a dungeon.
 * In Red Dead Redemption, John initally travels to Mexico on a smuggler's raft down the Rio Grande, while taking fire from enemies on the riverbank, in an event that takes several minutes to get through. When he gets to Mexico, he can travel back to the U.S. by going over an enemy-free bridge, or fast-traveling instantly.
 * In Pool of Radiance: Ruins of Myth Drannor there is an interesting example: Early on, when you visit the elve's hideaway, there is a tunnel in the cliff-side, however when you first investigate it its completely walled off. Later, as you progress through the ruined city you find passages that lead to the surface, all out through that tunnel, which is an incredibly useful tool compared to traversing the immense dungeon in order to leave and sell your junk. Oddly, the tunnel is on the opposite side of the surface map from the dungeon entrance, and many of the passage ways are on the far end of the dungeon (So it becomes something like so: Surface Passageway -> Entrance -> Inside Passageway). The passageways, are however two-way, so once you find them, you rarely have to go back to the main door unless you have to explore more of the main halls on that side.
 * Alundra 2 does this a couple of times: In the first room of the Ox Tank dungeon, there's a conspicuous locked door that turns out to lead to the boss room, and the Demon Whale spits you back out once you complete the dungeon inside of it. In addition, each of the three ancient ruins dungeons contain warp pads to the other two.
 * The Etrian Odyssey series has made it a staple to include hidden shortcuts in dungeons that can't be entered when you first come across them, but, when after a lot of exploration you look at your map and see you ended up on the other side of the wall, you can "break open" the shortcut, not only offering a much faster way back but more importantly giving a much quicker way forward the next time you enter the dungeon. These conditional 2-way shortcuts were fairly uncommon in the first game, but by the third game, having a shortcut between the entrance and exit of a dungeon floor is almost guaranteed and most floors have 3 or 4 other shortcuts. The first Etrian Odyssey game also has a shortcut right before the final final boss all the way back to the entrance of the dungeon, giving the player a chance to save the game before plunging in.
 * In Soldier of Fortune II, you take a long circuitous path through the Prague Hotel, itself containing several useless doors to before, to reach Dr. Ivanovich, then it's just a short run to the back door from there, which dumps you in an area you traversed in the first level.
 * The Marathon series often uses these, sometimes they're useless (Arrival), other times they're required to exit the level (Two Times Two Equals, Ingue Ferroque, All Roads Lead to Sol), or are a convenient shortcut back to the main area after new passages have opened (No Artificial Colors, Where Some Rarely Go). In some cases (Cool Fusion), you really do have to backtrack the long way.
 * In both Ys I and IV, Adol finds himself Locked in A Room at some point, then Dogi the Wallcrusher smashes a hole in the wall leading back to the beginning of the dungeon. Some of the games give you a warp item to quick travel to previous areas, which may stop working after the Point of No Return.
 * All 4 campaigns in Guild Wars end with the character winning the final mission, going to a "victory celebration area", than leaving that area to an earlier outpost. The most fitting example is probably the Nightfall campaign, where the last few missions involve the character getting taken to a realm in another dimension, fighting through several missions to finally kill the Big Bad, than leaving through a portal to the big city on the starter island.

Film

 * In an example that either inspired or was inspired by this trope, Conan the Barbarian and his party end up right where they started in Conan The Destroyer by smashing through a wall.
 * Used well in National Treasure -.
 * In The Book of Secrets -.

Literature

 * There's an example of this in the WIP Gender Swapped novella in Chapter 3. Jess notices Tess leaning against a door which was noted didn't have a doorknob. Later, after a couple hours, an elevator ride, a Monty Python skit, and several other random events that take place Behind The Scenes of the hotel. The two eventually end up on the other side of the door.

Live Action TV

 * Lost had something similar in season one. The Losties spent about half a season trying to get into the hatch, then when they finally get it open, they have to abseil down as the ladder is broken. Once inside, it turns out there's a door leading outside.
 * The creators confirmed that this was actually a mistake, as they should have been able to get in through that door.
 * How is that a mistake? No one on the outside knew about front door. Also, they couldn't have gotten in, it also was locked. (Although Desmond would have been more likely to open the door if someone was pounding on it.)

Tabletop RPG

 * Dungeons and Dragons. At the end of EX2 Dungeonland, a door in the Mad Feast Hall (the last encounter) takes the PCs back to the Magic Mirror house where they first entered the adventure.

Western Animation

 * The Simpsons plays this for laughs when Mr. Burns decides to shut off power to Springfield. With Mr. Smithers, they enter a passage behind a bookcase through Burns' office, slide down firepoles, gain access to a vault via retinal scanner, and reach the main power room...where they then shoo off a dog who got in through the room's broken screen door.

Real Life

 * Most movie theaters are designed like this, with a long, convoluted pathway that leads past the box office, a concession stand or two, and the ticket taker before reaching your theater. The way out, on the other hand, is often a one-way door that takes you directly out to the main lobby or even the parking lot.
 * The same for emergency exit doors, at least to a lesser extent.
 * Seattle's Children's Hospital, and probably others, has "staff only" corridors that can only be accessed from the outside with a security badge (unless it's an emergency); for others to access the area, they must take an elevator from a different floor, but the door can be opened normally from the inside.
 * Concert venues are similar and for the same basic reason; they need to check tickets on the way in (so need to filter people), but not on the way out (so they just want everyone to leave as quickly as possible so they can clean up).
 * The Winchester Mystery House has several rooms with one-way doors, forcing you to take the long way around to get back out.