The Vault 108 entrance area is inhabited by a colony of mole rats. The Vault 108 living quarters and Vault 108 cloning lab are inhabited by a dozen clones named Gary, all of which are hostile.
With the exception of Gary 1 and three other random Garys, all other clones initially are unarmed, or use melee weapons. Their AI, however, may direct them to pick up stronger weapons that may be nearby.
On the Vault-Tec computer in the Citadel, the premise of the experiment was explained to study conflict for leadership and power in a Vault. The Vault Overseer was known to have a genetic predisposition for a rare form of cancer that was expected to kill him within 40 months of the experiment's inception, and positions of authority in the Vault went unassigned and discretion was given to the Overseer. The main power supply was also scheduled to malfunction after 240 months (20 years while the vault was planned to be sealed for 38), and the back-up power supply was intentionally insufficient to meet the Vault's needs. On top of all this, the Vault was given three times the normal armory stock and no entertainment recordings.
There is a holodisk found in the cloning lab (A on the map) (located near a body near one of the examination tables, this room also has a very easy locked safe in it as well as Gary 12 and 36) that hints about the fate of Vault 108. Every time Gary was cloned, it immediately became hostile to non-clones, with each one becoming more violent. After the 53rd was no different, the staff began to wonder what to do with all of the clones, as the Vault's observation rooms were becoming full. The other entry in the holodisk says that Gary 54 was the same way, having injured Doctor Peterson during an examination.
The entry also states that they will be destroying some of the clones, to make room for "many more tests." What happened next is not clear. What is clear is that the only survivors are the Gary clones.
A Stealth Boy is between two terminals in the northwest corner of the room with the door to the living quarters.
A Nuka-Cola Quantum is behind shipping crates in the narrow room east of the door to the cloning labs.
A Tumblers Today is under the same stepladder the Nuka-Cola Quantum is sitting on. It can't be picked up with perspective tricks or fancy footwork but it can be taken. See the bugs section of the Tumblers Today page for how it's done.
Bobblehead - Charisma - Located in the Vault cloning lab on a table in the observation room (located in the center of the map), which looks into the main operating room. If you get lost, go to the black operating tables (one should have a skeleton on it) and look through the glass into the observation room (or the room with four beds). There you will see the bobblehead on a table beside a microscope.
The holodisk in the cloning lab ("Cloning log") that slightly explains the events of Vault 108 is in the room where there's a black cube safe that can be lockpicked. Look for a skeleton on the floor next to an examination table; the holodisk is close by.
In the Outcastoutpost where the Anchorage simulation is located, you can find the dead body of Gary 23. Presumably he left Vault 108, was captured by Brotherhood of Steel Outcasts at some point and taken to the outpost. It looks like there, the outcasts tried to convince him to enter the simulation as he had a Pip-Boy 3000, the correct interface device, but soon discovered that the only word he said was "Gary" and he was hostile to all non-clones. They grew impatient with him, and he was beaten to death with some brass knuckles which can be found close by. The outcasts then sawed off his arm in a futile attempt to remove his computer. His body has been unceremoniously dumped in a corner. This and the trail of blood on the floor from the beating and amputation indicate that the incident happened not long ago, and the Outcasts have not had time to clean up.
A cut audio holotape would suggest that Gary 23's arm was sawed off by the Outcasts while he was still alive, without the beating.
This vault is almost the most deteriorated vault located in the Capital Wasteland. The inside has completely rusted away over the years, the vault jumpsuits are the dirtiest of all, and it appears as if the only major loot in the vault is the Vault-Tec bobblehead located in the cloning lab.
Because of this deterioration, Vault 108 is the only Vault in the Capital wasteland without a single working terminal.
Just like Vault 87, Vault 108 does not contain a working Vault door control pad. To open the vault door you have to walk up to the main door and select the option to open it.
The Overseer's office is inaccessible, and also has a different window than other Vaults in the region, as it is rectangular, instead of round.
Although Vault-Tec records state that Vault 108 had triple the normal armory stock, no trace of this armory can be found when the Lone Wanderer arrives in 2277.
While the Gary clones do count as people killed, they will not drop fingers or ears for the Lawbringer or Contract Killer perks.