Vault 106

Vault 106 is one of the Vault-Tec Vaults located in the Capital Wasteland. It is located within a large cavern southeast of Arefu, directly south of Kaelyn's Bed & Breakfast, and a bit north of Jury Street Metro station.

Background
As part of the Vault Experiment, psychoactive drugs were released into the Vault 106 air filtration system 10 days after the door was sealed. By 2277, the vault's interior is mostly destroyed, and filled with insane survivors. The psychoactive drugs are still being pumped through the vault's air filtration systems, as evidenced by the player's vision suddenly being shaded blue at the same time that hallucinations appear. Information in the vault's computer terminals reveals that the Overseer knew that the inhabitants of his vault would be fodder for drug testing and he instructed his security personnel to tell those in the vault that everything was fine. At the very end of the vault is a cave-like area, where skeletons and other items are located, including a mini nuke, suggesting some of the vault dwellers may have been trying to blow their way out.

Enemies
When first encountered, the survivor will activate a Stealth Boy. (This is evidenced by the fact that your non-human followers will have a hard time shooting the Survivor as well; if it were a hallucination, only the Lone Wanderer would have difficulty). The Stealth Boy will remain active until the survivor is killed. The player then has a hallucination in which the Tunnel Snakes (Butch DeLoria, Wally Mack and Paul Hannon) from Vault 101 attempt to kill the player. After the survivor sustains some damage, the Tunnel Snakes will use Stealth Boys and flee, and the player will see as if in a hallucination (with the purple tint). This will end after killing the survivor. It is worth noting that if the Tunnel Snakes are killed by the Lone Wanderer or if the player uses the Mesmetron on them in the hallucination, they just disappear without leaving a body behind. Both killing them and them fleeing ends the hallucination.
 * Several insane survivors inhabit Vault 106. They wear Vault 106 jumpsuits and wield a variety of melee weapons, such as lead pipes, knives, baseball bats, pool cues, Chinese officer's swords, sledgehammers (at high levels), etc. Despite not wearing armor, the insane survivors are slightly tougher than the average raider.
 * A "survivor" (who has the same ambient/combat voice files as a raider) is on the lowest level, at the end of the science lab section, wearing a Vault lab uniform and wielding a baseball bat.

Living quarters

 * The Science bobblehead is located in the living quarters. After you first enter the living quarters (it's a two level room: top level), enter the door on the far left hand side of the room, diagonally across from where you first enter. Proceed to a hallway into a fairly large room (for a vault); this room has 3 windows on each side that look into a subterranean cave. The bobblehead is on a bookshelf against the back wall (3rd shelf)
 * A copy of Nikola Tesla and You is inside the classroom in the living quarters - the room to your left after you first enter the living quarters area. It's hidden in the bottom wooden box of those stacked on the teacher's desk.
 * A poem entitled "Scribbles" is found on a table with a monitor on it, near the entrance to the Overseer's office.
 * To anyone who gets this - A note, right in front of the locked (average) door south in the local map. It is written by a non-insane vault resident.
 * Feel the love man - Another note, downstairs in the left most room of the male dorms. It appears to have been written by one of the insane vault residents.

Science lab

 * A book Tumblers Today is on the science lab level. From the entrance, head straight down the corridor and take the stairs to the right. It's the first door on the right after the stairs, in the large room with all the machines. Turn left after entering and head to the back of the room - the book is on top of an overturned machine, near to the window (two bottles of milk are also on top).
 * A mini nuke is in the final room of the science lab area, just past the fight with the Vault 106 survivor.
 * There are two Vault 106 master keys located in the Vault. One can be found next to a functional computer terminal in the northwest corner of a room in the living quarters that is only accessible through the science labs. (You can see the room and the science lab's door through barred windows in the living quarters, but you have to go through a door in a room with a reactor in the labs to get to it.) There is also a hidden key at the bottom of a shelf in the store room, behind the one where you fight the Vault 106 survivor. This key cannot be picked up without using the tcl command and going as close as possible to the key.

Behind the scenes

 * Several additional hallucinations were planned and partially implemented for Vault 106, including a room appearing upside-down for a short time, a hallway where the Lone Wanderer would gradually shrink as they progressed along it, hallways appearing where blank walls had been before, and the "boss" survivor initially appearing identical to the Lone Wanderer's father. Most of these were cut for unknown reasons.
 * In addition to the unused hallucinations, a special helmet called the makeshift gas mask was placed in two locations within Vault 106. Wearing the mask would have prevented any further hallucinations from happening.  The mask was mostly implemented, but suffered from a scripting flaw which permanently re-applied the blue tint whenever it was removed, even outside of Vault 106.
 * A few unfinished areas which are inaccessible from the rest of the vault exist in-game, but cannot be visited through normal means. These areas resemble server rooms, with computer terminals in the area that can be accessed to reveal an entry titled "A Note to Me". Several notes with this same name are distributed on multiple terminals in the area, and after reading a couple of them, they will all change to say "Forget it, I'm through talking to you." These terminals appear in rooms appearing in the final game.

Appearances
Vault 106 appears only in Fallout 3 but is mentioned in Fallout Bible 1 and in a cut section of Vault 13's voice interface terminal in Fallout 2.

Bugs

 * The hallucinations of your Dad that appear throughout Vault 106 are always the default Caucasian model, even if you choose a different race for your player character (and thus also for your father).
 * The game sometimes defaults your body (though not the head) model to the default Caucasian model, staying that way until you reload the game.
 * At higher levels when attacking the Vault 106 survivor, even though the survivor might be dead, the Tunnel Snakes will literally "float" into the room without the blue hallucination backdrop. Killing them grants experience points.
 * If you shoot at Amata she will disappear, but if you kill her with one shot you will receive negative karma and her clones will turn hostile towards you but, upon reaching you, they'll just stand next to you giving you an angry look with their fists up.
 * Despite the insane survivor's natural hostility toward the player, dropping a live grenade on them grants bad Karma.
 * Some hallucinations that are targeted in V.A.T.S. will cause the game to crash if they disappear while V.A.T.S is zooming in or the player is taking out their weapon.
 * If you shut the main Vault door (the round one) it will appear as if it is not shut all of the way. Another way to see this is to leave the door open and you will see that it is in fact pulled farther back than the rest of the vault doors in the Capital Wasteland.
 * After having killed the Survivor, if the player attacks his/her corpse the blue hallucination tint will appear.
 * Sometimes after killing the Survivor, his/her eyes will blink even though he/she is dead.
 * If you go into the overseer's office and jump near the wall to the right, near the terminal station, you will fall out of the map. One way to get back is to step into the void, and you will teleport back into the hallway before the office.
 * The other is to land on the overseer's tunnel as soon as you jump through the wall, face their office and move all the way to the right, and then jump out through small gap in the map to land on a tunnel below (you will lose some health). From there, turn right and ascend the top of the stairs that are the furthest away, forward, from you.  After you have reached the top of the stairs, continue heading forward until you reach an opened door, directly East of the door to the Vault Entrance.  If you have not yet encountered this hallucination event, you will be teleported into the hall if you close the door and walk over it.
 * Sometimes the game will malfunction, causing the hallucination of Paul Hannon to become real. You can kill him and get a mint-condition Tunnel Snake outfit off of his body.