Myopic Architecture

"The materials used to create a lock are of utmost importance. Shoddy brass or copper will give way to a well placed kick, thereby rendering the lock itself useless. I recommend steel over iron when choosing a material. More robust materials tend to be prohibitively expensive and necessitate the door being made of similar metals. I have been chagrined to stumble across the shattered shell of a wooden chest, its dwarven lock intact and still locked."

- Proper Lock Design, The Elder Scrolls IV: Oblivion

This door is absolutely impenetrable. It's made of 100% Indestructium, is guarded by robot monkeys with crossbows, and opens only to authorised personnel who pass the DNA test, pass the retina scan and present a valid birth certificate. Yes, no one will ever force his way into — did you just break the door off its hinges?

This is Crippling Overspecialization applied to architecture. A designer puts immense effort and resources into a structure, most often a defensive point such as a wall, door, or window, but fails to notice a large weakness in the design that makes all of this easy to circumvent. The most common flaw being that for all that the door itself is indestructible, the wall around it is less so. This is especially so in Chinese and Japanese media where many walls are made out of paper. Often, the floor will also be vulnerable to burrowing. The door itself may not be that hard to open, especially if We Have the Keys. Often played for laughs if the way through the apparently impenetrable defense is particularly obvious or easy.

Compare Dungeon Bypass, Cutting the Knot, Steal the Surroundings. Contrast There Was a Door.

Advertising

 * Played straight in a TV ad for a French reinforced door company: France's equivalent of a SWAT team is raiding an apartment building and hits a particular door with a battering ram: This only makes a huge hole in the wall around it, with the door and its frame still standing.

Comics

 * In Doctor Strange: The Oath, a door is sealed with a magic sigil. Strange asks Wong to break the door down. Seconds later, the Night Nurse calmly picks the lock with a hairpin.

Film

 * Pirates of the Caribbean presents a lesson: Don't build a jail door using half-pin hinges.
 * Star Wars has The Death Star. Surely no one would shoot missiles into an open chute that leads directly to the main reactor. And it wouldn't hurt to place said chute at the end of a long valley that puts any attacking fighters out of shot from the defensive guns.
 * This is heavily lampshaded in the Family Guy version.
 * As for the guy who was responsible for that flaw? The Emperor personally executed him. The engineer went on to design the *next* Death Star as well. And every time he messed up, the Emperor would use a new method to kill the engineer before putting him right back to work with memories of the death intact.
 * Justified with Helms Deep in The Lord of the Rings, as the designers could not have anticipated that Saruman would use explosives, mostly because he apparently invented them just for this battle.
 * There are many examples where someone is prepared to break down the door when someone says, 'wait' and turns the knob of the unlocked door.
 * In The Pink Panther Inspector Clouseau is prepared to shoot the lock when Mr. Tucker says, "Don't do that old man" and opens the door.
 * In Red, Bruce Willis circumvents a password-protected lock that he describes as "unbreakable" by kicking a hole in the flimsy drywall next to it and opening the door from the inside.

Literature
"Six Beneficent Winds: But you can't go through walls!
 * The main gate of Redwall Abbey is large and thick, impervious to even the most dedicated of sieges. Basically, not one invading vermin horde has ever gotten through it. The tiny wicker side-gate, on the other hand, has been breached by countless invading hordes over the seasons, probably accounting for every successful invasion of the abbey. This is presumably intentional, since it would be easy to station three well-armed, armoured guards there during a siege to hack up any single file intruders who tried to get in. Unfortunately, being peaceful monk and villagers, the Redwall inhabitants never think of that.
 * In The Bellmaker, the heroes are able to escape their prison cell by hacking the hinges (which are on the inside) off.
 * Which is justified, as the heroes' "prison" was a peaceful residence, and was invaded practically only weeks back. The occupiers locked the heroes into the tallest tower, i.e. the place with the least chance of escape (but it is highly suggested -because of it being the tallest tower-, that it probably was the keep, and hence built defensively. Therefore, the hinges naturally were on the inside]].
 * In Guards! Guards!, Vetinari is revealed to have done this on purpose: while the lock to the palace dungeon is on the outside, the locking mechanisms are on the inside. Would-be usurpers throw him in the dungeon expecting it to serve as a Tailor-Made Prison; instead, it's an impregnable fortress that he can "escape" at his leisure.
 * In The Last Continent, Rincewind discovers that the cell doors in the XXXX jail have thick bars, sturdy locks... and weak half-pin hinges.
 * At one point a point is made of the wonderfully-made reinforced hinges on the door of the notorious bar The Mended Drum. The point made is that they held up beautifully as the whole frame was ripped from the wall.
 * In Interesting Times, Cohen and the Silver Horde are more or less free to roam about the castle, due to being the only ones who think to walk through the paper walls.

Cohen: Why not?

Six Beneficent Winds: They're - well, they're walls. What would happen if everyone walked through walls? What do you think doors are for?

Cohen: I think they're for other people."


 * In Anansi Boys a police specialist bemoans Graham Coates' security arrangements, pointing out that he installed a wonderfully secure door, then hung a lock on it that the specialist picked effortlessly.
 * In Artemis Fowl Butler destroys an ancient stone doorway because it's much weaker than the modern armored door.
 * In one of Christopher Anvil's Interstellar Patrol stories, the villain boasts of how impregnable his Elaborate Underground Base is. When the protagonist puts this to the test, he finds that neither the villain nor his contractors realised that it's no good having foot-thick walls if they only go up to ceiling height, with a convenient access void above them.

Live Action TV

 * In one episode of The Mentalist, the Victim of the Week was killed via exposure to a deadly virus kept in a high security vault accessed by retina scan - which didn't work right and would let in anybody who presented their eye for scanning.
 * A minor example in The Sarah Connor Chronicles, someone shuts a metal security door in their faces, and Sarah asks Cameron if she can get through it. Being a Terminator she could given time, but it's faster to punch a hole in the concrete wall. Of course, the person they were going after was expecting human pursuers, against whom the wall would have been sufficient.
 * A common conceit in Michael Weston's voice-overs on Burn Notice is that people are more apt to reinforce doors than the nearby walls.
 * In an episode of MacGyver, he's at a college supervising a day in which students who have locked the doors of their dorm rooms in various creative ways change places and try to open them.  This plot was based on an actual annual event at Caltech.

Manga & Anime

 * In one chapter of Keroro Gunsou, the Keronians test out their new security system on Momoka's mother Oka, who wants to get her hands on Keroro for some reason. The first obstacle is a series of electronic locks on the mini-fridge that serves as the main entrance to the lair. What does Oka do? Rip the door off its hinges.
 * In the finale arc in the manga Ranma One Half, Akane is held in a cell by the bird tribe. She desperately tries to kick and ram the bars through to no avail. In her frustration, she leans to one side... and tears open the flimsy lock on the cell.

Newspaper Comics

 * There is a Hagar the Horrible strip where Hagar returns from a-plundering, handing Helga a large, well-crafted castle-style lock, noting that she's been worried about people breaking into their house. She's initially overjoyed, untill she asks where he got it. "Oh, it wasn't too hard — it only took me five seconds to rip it out."
 * In a Gnasher and Gnipper strip, after the dogs knock over Dad one time too many, he buys a pair of special gnash-proof chains to keep them restrained. Fortunately for the dogs, while the chains were completely gnash-proof, the wall wasn't.

Tabletop Games

 * Happens more often than you think in Tabletop RP Gs; savvy players always check hinges, floors and walls when attempting a Dungeon Bypass, and inexperienced G Ms don't always plan for this.

Theater

 * In A Very Potter Musical Ron assures everyone that Voldemort can't get in, because he's barricaded the door. Seconds later, Voldemort enters through a curtain right next to the door.

Video Games

 * Often exploited by Revan in Knights of the Old Republic.
 * The Big Bad of Second Sight
 * In The Secret of Monkey Island game, if you let Guybrush be recaptured by the cannibals, they'll progressively beef up the security of their prison hut, eventually installing an all-steel door with a motion detector, never thinking that there might be a large hole in the hut floor.
 * Similarly, in Leisure Suit Larry 7, the door to the staff room is heavy steel and, if you get too close, about a hundred weapons emerge from the walls to point directly at your head. Security measures include testers for DNA, fingerprints, retinal scans, tongue prints, and urine analysis. But, it turns out, the latch doesn't work properly and you can get in by just pushing on it.
 * Similarly to the Pirates example above is the cell door on the pirate island in Shadow Hearts: To The New World. Natan just lifts it up and walks out.
 * Oblivion discusses this, as quoted above.
 * A common mistake for newbies to Dwarf Fortress, rarely realized until the fort's defenses are put to the test.
 * Jagged Alliance 2 has several locations with doors that are extremely difficult to lockpick and resilient enough to withstand a blast from an anti-tank rocket. The walls these doors are placed in, however, are completely ordinary and can be blasted to rubble with an ordinary dynamite stick.
 * The Geomod engine from the first Red Faction game let the player destroy just about anything in the environment. Bulletproof windows, however, were completely indestructible. The walls around them were not. With enough explosive, a player could leave a glass pane floating in the middle of a twelve food wide void.
 * In The Legend of Zelda Majoras Mask, the gate to the castle of Ikana is sealed and cannot be opened by any means... too bad there's a big hole in the wall right next to it.

Webcomics

 * Homestuck. HB: Pry the wall from the safe. (Unfortunately, "That notion is even more ridiculous than the last one.")
 * Sluggy Freelance uses this trope twice in the Sluggy of the Living Freelance storyline.

Western Animation

 * Played for laughs in The Simpsons: One scene in the nuke plant in "Last Exit to Springfield" involved Burns and Smithers going through several layers of increasing security to reach a control room, which was seen to also feature an ill-fitting, flapping screen door leading directly to the parking lot, through which Burns has to shoo away a stray dog.
 * In an episode of the 1967 Fantastic Four, Diablo is running from Thing and retreats into a panic room. He assumes he's safe, since the door is made of titanium, which Thing is not strong enough to break. When Thing reaches to room, he just breaks through the wall.

Real Life

 * After a long and bloody siege that they had pretty well held off up to that point, Constantinople finally fell when someone left a small supply gate open, allowing the invading army to come in.
 * The World War II Maginot Line is widely seen as an example in the popular imagination, but is not so.
 * Cryptography brings us the "Single Point of Failure". Basically, if each part of your system is secured with a different password, a cracker who gets just one of those passwords will have a hard time doing much damage. But if you use the same password for everything, you're hosed.
 * Cryptography has this issue in more ways than one. There are branches of mathematics devoted to developing crypto-systems that are pretty much mathematically guaranteed to be secure. However, once these systems are developed, they are turned over to people who use passwords like "password" or leave their login information on a little sticky note on the monitor.
 * Computer Security is pretty much governed by this trope. Unlike other security systems, an attacker doen't get hurt if they fail to break in. So they simply try every conceivable way into a system.
 * Thus leading to the following expression: "The user is the biggest threat to any security system."
 * Because of this trope is that the Jules Rimet Trophy (the first trophy used during the world cups) was stolen so easily. When the Brazilian team won the cup for the third time in 1970, they were allowed to keep the real trophy in perpetuiry, since Jules Rimet stipulated that in 1930. It was put on display at the Brazilian Football Confederation in Rio de Janeiro encased in bulletproof glass so it wouldn't be stolen. The problem was that the rear of the cabinet was made of simple wood, so in 1983 it was easily opened with a crowbar and stolen. Sadly, it was never recovered.
 * Truth in television: Some of the better deadbolts can withstand forces that would put a hole in an outer wall. And, of course, there are a lot of houses that have solid steel doors with deadbolts and security screen doors... and great big picture windows right next to them.
 * Straitjackets are designed this way, in that someone who's both mentally-rational and moderately flexible can often work their way out of them after a few tries.