Vault 3 Vault 3 is one of the Vault - Tec vault s in the Mojave Wasteland . Except for some flooding in the lower levels , the vault is still mainly intact in 2281 and is now occupied by the Fiends , who killed the vault ' s original residents . Background . Vault 3 is one of three vaults in the Mojave with human inhabitants , the others being Vault 21 and Vault 19 . This vault was one of the few control vaults that had no experiment connected with it , and it functioned almost exactly to the residents ' expectations . Control vaults were designed to open after 20 years , but the residents of Vault 3 decided to keep it sealed far longer , out of concern for the possible dangers they might face outside the vault . All was going well until an accidental water leak occurred , forcing the residents to open the vault to find help . The original Vault 3 inhabitants opened their doors and began to trade with people outside the vault . For a time , it went well and the inhabitants made a good living . However , this also brought the vault to the attention of the Fiends . The inhabitants hadn ' t set up any security , so the Fiends found little difficulty in raiding and taking the vault . In many ways , Vault 3 was the ideal post - apocalyptic community that had all too often evaded Vault - Tec ' s many experiments . The vault ’ s isolation didn ’ t affect the residents . They maintained an orderly , democratic society , and , unlike other vaults ( Vault 101 in particular ) , the overseer wasn ' t a dictator or a megalomaniac . Once again though , as with so many other Vault - Tec designs , the water pipes failed , and by necessity the community was forced into contact with the Mojave ' s savage population which was ultimately their undoing . Location . The vault is located under a building in the South Vegas ruins and is the base of operations for a gang known as the Fiends . Its location can be gained from the colonel at Camp McCarran after volunteering to help with the gang problem , from Elder McNamara of the Brotherhood of Steel during the quest Still in the Dark , from during the quest Aba Daba Honeymoon or from Private Ortega in the barracks at the NCR Sharecropper Farms . The vault door , which is opened by the adjacent control panel , is connected directly to the South Vegas ruins and therefore provides no loading point for the vault interior . This explains the lack of a door opening sequence . Layout . Inside , the entrance is guarded by a female fiend , who will question you about what you are doing there . If you enter using a Speech check ( 64 ) or wearing Great Khan armor , you can navigate the vault without being attacked . You can remove the armor after the initial dialogue with the guard Fiend . If she becomes hostile , note that she levels with the player , giving her an abnormally high amount of hit points at higher levels ( a maximum of 260 at level 30 player ) . The walls of the vault are covered with graffiti , presumably done by the occupying Fiends . Much of the graffiti in the vault is the same as that which can be found on the Brotherhood ' s bunkers in Hidden Valley . In one of the toilets , there is graffiti on the wall of a stick man and woman . It ' s an enlarged version of the one in Hidden Valley . Overall there are about 5 hackable terminals inside the vault , which contain information about the vault ’ s history . Vault 3 consists of 3 areas : Recreation area . Vault 3 seems to have a much larger recreational area than the other vaults . The recreation area also includes several pool tables and some minor loot . There is a locked door containing multiple bottles and one and one . Within the recreation area there is a locked door leading to the maintenance wing . Living quarters . On the main floor of the living quarters there is a cage holding 3 captives : Rick Lancer , and Dennis . The cage also holds the body of the fourth captive , Carter , who managed to escape to search the vault for weapons before being caught and was subsequently killed . , the Fiend who holds the key to the cage can be found in one of the southernmost rooms of the living quarters ( see the unmarked quest " I Love Bananas " ) . Alternatively , the cage door can be picked without Karma loss , and no fiends will become hostile . Two of the rooms in the living quarters each have a deceased fiend on a bed , surrounded by empty syringe s , and . Around the southern part of the living quarters is a bedroom containing a terminal with an administrator " " Billy boy " " and a function called " " Compose Automated Blast Message " " . However this does nothing , stating that the system is offline . The flooded areas are long and difficult to swim through with enough time to return for air before taking drowning damage . In addition , the water is irradiated at 1 rad / sec . The rebreather or turbo will aid in searching these areas . Maintenance wing . The leader of the Fiends in the vault , Motor - Runner can be found in his throne room in the northern part of the maintenance wing along with his two guard dogs , BoneGnash and GhashBone . Notable loot . If the Fiends are non - hostile , looting will not make them hostile , nor will it cost Karma . Appearances . Vault 3 appears only in " " .