How did they become Mutants in the first place ? Well... B.J. was fighting Dr.Schabbs [In Episode 2 of Wolfenstein 3D] and B.J. unfortanetly lost and ended up becoming a mutant As for Doomguy He finished up clearing up a room full of Zombies and Demons and then took a which took to him to Dr.Schabbs and then Doomguy and Dr.Schabbs ended up battling each other , but unfortunately... Doomguy Lost and got turned into a Mutant