Somewhere in his Dexter profile it said "tranquility lane", location or something like that.
Tranquility Lane is a virtual reality simulation housed in Vault 112, created by Dr. Stanislaus Braun.[1] The Lone Wanderer is tasked with an escalating series of violent tasks ranging from making a child cry to killing residents. The tasks are given by a little girl named Betty, who in turn will free the Lone Wanderer's father, James, who is trapped in dog form.
As an alternative to completing the violent tasks, the player character may activate a failsafe, which will irrevocably kill everyone with the exception of Betty, James, and the Lone Wanderer. Both solutions result in the release of the Lone Wanderer and their father from the simulation.
https://fallout.fandom.com/wiki/Tranquility_Lane