Details (3)

Enter the vault area and find a small shack.

Go down the manhole in the shack to enter the Vault 15 cavern.

Kill the Lesser Mole Rat, which is the most troublesome enemy here. You can attack it unarmed or with a pistol.

Proceed to the command center and attempt to access the hallway leading to the main computer and overseer pedestal. You will receive a message stating the water chip is nowhere to be found and gain 500 xp.

Scour the area for additional xp, an SMG, and a leather jacket.

Upon entering the vault, kill all rats and collect flares from a locker in the first hallway.

Find healing items in a locker in the eastern hospital room.

Use a rope on the elevator to reach the second floor and the living quarters.

Kill rats on the second floor and enter a room with a locker containing a Leather Jacket and some rope.

In the northern half of the second floor, find FMJ ammo.

In the southwestern room's bathroom, locate a Hunting Rifle that blends in with the floor.

Use the rope on the elevator on the right-hand side to enter the command center.

Kill the mole rat guarding the command center.

Go to the southern area, then the eastern side covered with rocks. You will receive a message that the water chip cannot be found and gain 500 xp.

On the third level, in the armory (the room above the passage to the command center, containing lockers), find two frag grenades, a stick of dynamite, a crowbar, and a Sub-Machine gun (SMG).

In the eastern rooms on the third level, find more ammo.

In the library on the third level, find a first aid book and more ammo in a locker.

After collecting usable items and killing rats, head back to Shady Sands.

To receive 200 experience for finding the source of the rat infestation, go to the conference room, located north of the room containing the SMG.