after Doom 2 doom guy thinks.Hey yah know the UAC kinda suck.And then doom guy goes to every bunker and space station killing everyone then comes the last bunker.
When arriving at the entrance doom guy pulls out his chaingun(or m16 if you use the other wad thats not required )and gets to work then he sees the demon fall and puts the super shot gun to his head and pulls the trigger.He wakes up in a small room with about 9 of his nightmares and a BFG 9000 in front of him.