Code Emergency

Announcer: "Will Mr Fire please come to the flammable items gallery?"

—The Museum of Everything

Uh oh. A customer puked and you need to avoid a Vomit Chain Reaction. Or perhaps you've just spotted a disgruntled ex-employee walking in the doors carrying a semi-automatic. Maybe there's a fire in the building but you don't want to evacuate just yet.

Fortunately you have a pre-arranged code for just such an emergency and you can put out a message that will alert your co-workers to the situation while leaving your customers none the wiser!

See also: Code Silver. A subtrope of Trouble Entendre.

Examples of Code Emergency include:

Anime and Manga

The mall in Code Geass has a prearranged message to announce an attack by terrorists.

Film

In Johnny Mnemonic Dr. Alcome is code for a general call to doctors when the clinic needs lots of help, but doesn't want to spook the patients. Amazingly, one of the characters doesn't get it and has to have it spelled out for her - All come.
- This is also at least partly Truth in Television, as many hospitals will use this code if they need a lot of medical personnel in a particular part of the hospital (e.g., "Doctor Alcome to the emergency ward.")
In Lean On Me, Principal Clark declares that, when the fire inspectors are spotted, he'll announce a "Code 10", subtly telling the staff to get the chains off the doors. Of course, the idea is kind of ruined when the inspectors do come, and he starts screaming, "Code 10! Code 10! This is Joe Clark! Get those chains off those doors!" over the radio. What an Idiot!!
In Monsters vs. Aliens, a guy at a UFO-spotting station in Antarctica is rather shocked to actually pick up something, and on the verge of panic calls in to headquarters to report a "Code Nimoy".
John Woo's Broken Arrow gets its title from such a code. "Broken Arrow" is code for an accident involving nuclear weapons; in the film, a weapon is stolen (known as an "Empty Quiver") under the pretense of such an accident.

Giles: I don't know what's scarier, losing nuclear weapons, or that it happens so often there's actually a term for it.

Die Hard: McClane ferrets out the fake "police dispatcher" by subverting it: using the wrong police 10-code to describe his situation. When the dispatcher smoothly claims that all units have been dispatched to his code,

"You mean you had to dispatch all units for the naked people wandering around?"

In A Beautiful Mind, when the main character is in hospital, the staff uses "code red" for when a patient starts cutting himself.

Literature

Different codes are used in Chuck Palahniuk's Choke, by a renegade mother to covertly contact her son.
- Also by the hospital looking after her... when Nurse Remington is summoned to the front desk, it probably means you have outstayed your welcome.
One Running Gag in Robert Rankin's Armageddon II: The B-Movie was to have police disagreeing over which code was specifically required for a particular emergency. (Since they included "demon-possessed vehicle in a towaway zone", we can safely say that whoever came up with the codes is either very Genre Savvy or Crazy Prepared.)
In the Modesty Blaise novels, the name "Jacqueline" inserted into any conversation is Modesty and Willie's private signal for 'I'm in trouble and can't talk openly.'
The City Watch Discworld Diary contains a clacks-based parody of police emergency codes, with codes for crucial messages such as "Knocking off early for lunch" or "Gargoyle officer ate messenger pigeon (message included), please re-send".

Live-Action TV

Played with in Chuck, where the staff have "Code Pineapple" to rapidly evacuate the store in case of emergency, but when they actually try to implement it they manage to induce a panicked stampede for the doors. Which, ironically, helps to avert the actual emergency.
In the Grey's Anatomy episode "It's the End of the World," "Code Black" is passed between doctors and staff. It apparently stands for an explosive on the premises, which in this specific case is encased in the innnards of a man about to undergo surgery.
- Hospitals do have codes for a large number of unbelievably unlikely situations. The horror comes when you realize there wouldn't be a code for it if it hadn't happened before.
On Kings Silas' staff has a "code for when [he takes] too long in the bathroom".
- Which is a funny reference to the Biblical story where a Israelite assassin was able to escape because all of the guards and servants assumed that the king (whom he has just killed) was simply taking his time in the bathroom.
Scrubs played with this once (as well as having some straight uses of it). J.D. fakes getting a 'Code 3' on his pager to escape a patient. When asked by the patient what it is, he replies "It's worse than a Code 2 but not as bad as a Code 4" and hurries out of the room.... barreling straight into a stretcher placed across the door and pitching headlong over it. Carla, still standing in the room, comments "That's a Code 2."
In Red Dwarf, upgrading from a "Blue Alert" to a "Red Alert" requires manually unscrewing and replacing the colored flashing lights.
- In the episode Back in the Red, Cat suggests they forget Red Alert, and go straight to Brown Alert.
Parodied a bit in the new generation of Doctor Who, when the Ninth Doctor gets a color coded emergency, Code Mauve, which is apparently the galactic standard. Earth's normal Code Red, apparently, is camp. "All those Red Alerts, all that dancing."
Parodied in Community episode "The Politics Of Human Sexuality" when the security officer informs Dean Pelton that there's a 'five-nine-seven' currently occurring in his office:

Dean Pelton: "There's a dog-fighting ring in my office?!"

On The West Wing, characters used a code to get someone to immediately stop whatever they were doing, come quickly, and not ask questions by making a casual reference to an "old friend from home."

Radio

The Museum of Everything often lampshades these messages. As well as the one in the page quote, they've had:

'"Can Inspector Bomb please come to the suspicious packages gallery?"

Tabletop Games

Paranoia has a few dozen of 'em, such as Code 15 ("traffic accident") or 38 ("renegade mutant using unauthorized mutant power") or 54 ("free Hot Fun back at Central"). Confusingly, numeric codes are also informally used to gossip about how many clones you'll need in order to survive a mission; clones normally come in six-packs, so when a "Code Seven" mission comes along...
Mage: The Ascension: The Technocracy has Code Ragnarok for Godzilla Threshold events. It authorizes the use of the entire Technocratic arsenal, including WMDs, a 100% civilian casualty rate and a 100% operative casualty rate.

Video Games

In Modern Warfare 2, there's a scene in which the hijacking of a Russian submarine with nuclear missiles takes a sudden turn for the worse. Much, much worse. Everything Ghost can do is scream "Code Black! Code Black!!!" and watch a nuke heading for the US.
Lampshaded completely in Final Fantasy XIII when boarding the airship Palamecia: When first intruders are detected, the bridge declares Code Red, which later is raised to Code Green and eventually Code Purple. But it gets redicolous once the intruders disappear from the security scanners:

Col. Nabaat: "That means... we're Code Yellow. No, wait, Code Blue? If we were Orange, that would mean..."
Primarch: "Desperate times demand flexibility. Code White."

Web Original

The characters in the Robert A. Heinlein-esque The Saga of Tuck use American Sign Language, rotating numeric call signs and shortwave radios to maintain communications. It would probably be more light-hearted, seeing as they're all high school students, if someone hadn't nearly died.
Parodied in EVE Online machima Clear Skies. The title vessel has fifteen color codes; of these four are known: Code Red ("Imminent Ship Destruction"), Code Orange ("Imminent Judith Chalmers Encounter"), Code Yellow ("It's time to start running"), and Code Blue ("Armed incursion of the ship"). Charlie- who wrote these things- mentions a fifth code, Fuschia, though what it means is unknown.

Western Animation

In Generator Rex, Rex has problems keeping his codes straight. He once tells some friends not to worry as its "only a Code 2". When a giant EVO crashes through a building, he remembers that "the lower the number, the worse the situation".

Real Life

In William Poundstone's book Biggest Secrets, he mentions that hospitals use codes like "Dr. Red" and "Dr. Firestone" for fires, and "Dr. Strong" for patients who are putting up a fight. They do this because some patients may have heart attacks if they hear and comprehend the frightening news.
In live stage shows "Mr. Sands" means fire. So if you hear an usher being told "Mr. Sands is waiting in the dressing room" and then everyone gets quietly ushered out, you know why.
- This dates back to the olden days of fire buckets, which usually contained sand.
- It's also used in movie theatres.
- It is also heard in a train stations.
  - Alternatively heard as "Inspector Sands" in an underground station. Played on a loop repeatedly for five minutes and nothing happened.
Schoolbus drivers have a specific code they use while on the radio if they need to call for an officer or say there's a hostage or gun/knife/etc. on board.
Disneyland has a bunch of these sorts of codes. The most colorful is probably "protein spill" for when someone has upchucked. But the funniest is "101," which means that an attraction has broken down and is supposedly so called in honor of U.S. Highway 101 and its perpetual traffic jam.
Circus lore claims that the band will only play "Stars and Stripes Forever" in emergencies.
In the 1970s the ship-based Pirate Radio station Radio Caroline regularly broadcast numbers at 8 PM. Some of these were numerical codes representing different emergencies, but there were also a whole bunch of dummy codes so the listening authorities couldn't tell when the station was calling its office for supplies or assistance.
Code Adam is used in stores when a child goes missing. The store's doors are locked, and nobody goes in or out. A detailed description of the child and what he/she was wearing is obtained and broadcast over the store. If the child is not found in ten minutes, law enforcement is called. If the child is found and just lost, they are returned to their parent/legal guardian. If the child is found with someone other than their parent/legal guardian, employees try to delay their departure from the store without risking anyone's life.
- Now accompanied by Amber Alert, a police/emergency services program that also sees frequent use as an analogue emergency page for "missing/abducted child."
Hospital color/number codes are legion, and sometimes aren't even standardized between hospitals in the same system, let along hospitals in the same state. However, some calls are common enough to have generally recognized meanings:
- Code Blue/Code 99/CPR Team: cardiopulmonary emergency (code team responds; usually a team of nurses from ICU or Emergency, a house doctor, and an anesthesiologist or nurse anesthetist from the OR)
- Code Red/Red Alert/Dr Firestone: fire alarm, activate department fire protocol (close fire doors, move patients past fire zones, evacuate if ordered)
- Code Orange/Code Purple/Code Silver: internal incident (psych patient missing, active shooter in building, active bomb threat, etc; activate case-specific disaster plans)
- Code Black/Code Yellow/Code 10: external incident (natural or man-made disaster, incoming mass casualties; activate department disaster plan)
- Code Pink/Code Adam/Amber Alert: missing infant/child (lock down all exits, be on lookout for suspicious persons)
- Code Green/Code 00/All Clear: all clear, resume normal duties
  - There are informal codes too. "Code Brown" universally means... just about what you'd expect.
On film sets "10-1" is given to indicate when someone is in or on their way to the bathroom. This is because most communication is primarily done over walkie-talkies.
- For further clarification, radios can be a less than perfectly clear method of communication, due to various factors affecting the signals sent and received (interference from the building you are in, or electronic equipment/transmitters near you, or just something like a damaged radio antenna), so easy to recognize codes called Brevity Codes (or "Ten Codes", in the case of cops saying stuff like "Ten-Four") are used to quickly and clearly pass information along despite poor signal quality. The codes can of course also be designed to make eavesdropping difficult.
In one school district, a "Code 3.03 meeting" was known universally, even among the students, as the code for a bomb threat.
- "Mr. Falkes" and his parents being in the office meant bomb threat, "Professor Norris" needing to meet his wife in the teacher's lobby meant weapon/stranger on site, and a "ROTC Club Meeting" being canceled meant that something really, really bad was happening that required immediate staff-wide attention (via email or intercom). They had regular enough drills on the three... but never got around to testing the fire alarms.
At one college, instructors use a phone code to alert security that a student they're meeting in private may turn violent. If we want a security guard to linger near our offices as a precaution, we call the campus switchboard and say we'll be a little late for our meeting with "Dr. Barry"; if we want a guard to come in immediately, we say the appointment needs to be postponed. (Dr. Barry was a founder of the college, long deceased.)
Some student travel programs arrange codes with students that are departing for homestays in a foreign country. For example, a student in a bad situation could tell his/her family that it was the chaperone's birthday, and ask to call to congratulate her.
At one supermarket, the code for theft was 'Service 100' (it's changed since). The code for 'Two mafiosa guys are asking about what you did with the Don's daughter', apparently it was 'Service Oh, f-.
At one bar, they use one humorous code in particular (spoken over the phone); "I would like to order one anchovy pizza", it's a code that signals the arrival of the health inspector.
Walmart stores use a color-coded system, with various colors representing a different type of emergency.
If you spend a lot of time riding in airliners, you might have stopped noticing the various bings and bongs and chimes you hear over the intercom during the flight. Many of these are coded signals for the aircrew (specifically the flight attendants) to pass on routine information without disturbing the passengers. Sometimes, these codes can include messages about possible problems on the plane, but often are just a signal for the flight attendant to pick up the intercom phone to talk to the flight crew.
- "Brace, Brace, Brace" is the standard command on aircraft to prepare for a crash landing.
  - If by "prepare for a crash landing", you mean "Get in the brace position, if you'd be so kind, we're currently in the middle of crashing" and is usually given right before impact, usually less than thirty seconds before. Not really much of a Code Emergency, more of a "do this if you don't want to die horribly."
Transponder codes, known as a "squawk", are used to relay information about a particular flight and emergencies. 7700 is for a general emergency, 7600 for a loss of communications, and 7500 for unlawful interference (hijacking).
Since the theme park Sesame Place is supposed to be family friendly, staff are very restricted in their verbiage. Thankfully, they came up with interesting codes: Code Elmo-Bleeding/Blood, Code Zoey-Vomit. Code Snuffy and Big Bird are pretty obvious.
Many security organizations use the APCO ten-codes, under which an emergency is "10-33".
Disney Monorails used 10-codes, with some (alleged) additions.

SIGNAL 96-S: There's a huge snake on my train!

A Bay Area night club reported used the phrase 'Tango Nacho Underpants' as a shorthand code for 'someone is stripping on the dance floor'.
After the Erfurt massacre, German schools created the phrase "Mrs. Koma is coming" ("amok" spelled backwards) to warn staff of active shooters. It was later used during the Winnenden school shooting.