Like what if atlas wanted to make a movie about zombies and they had Gideon in it so this was probably before Mitchell was in atlas.
Or
What if it’s just Oz’s imagination? That would explain how random employees as the main characters. Maybe Oz was just bored at work and made up the Exo Zombies story in his head? But the ending wear he says what happend to everyone else in the story is what happens after Gideon and Mitchell stop the missile from launching. And Oz monologues the whole thing
https://vidmate.onl/ .
But that’s just a theory.