Raid of Vault 3

The raid of Vault 3 was the invasion and occupation of Vault 3 by the Fiends prior to or during the year 2281, resulting in the death of all Vault 3 residents.

Prelude
As a control Vault, Vault 3 stayed unopened until a water leak occurred, forcing the residents to open the Vault and search for assistance. Running a trading program, all went well for the inhabitants until the Fiends set their sights on the Vault for a new headquarters.

Raid
Since the Vault residents had set up no security, the Fiends needed little effort in raiding the Vault. According to Motor-Runner, the Fiends were let into the vault by the dwellers through the entrance sector and massacred every single resident in sight. The Fiends then occupied the Vault and set up their new headquarters inside.

Aftermath
The New California Republic turned their attention to the Vault, and sent a lone ranger into the Vault with the task of killing Motor-Runner and exterminating all the Fiends inside. He was shot in the leg, holed up near the residential area, unable to escape on his own.

Appearances
The raid of Vault 3 is mentioned and its aftermath appears only in Fallout: New Vegas.