A view of the front yard of the Atlas research facility is seen, as Oz narrates.
Oz (narrating): When Atlas dropped the bomb, they... hoped it would finish the war. Instead, it unleashed a freak show like no one's ever seen.
The scene then shifts to a prison, showing an unnamed Atlas soldier attempting to escape a horde of zombies, with Gideon aiding him from a Warbird after reaching the prison's courtyard. As Gideon looks at the zombie horde swarming the prison, he is suddenly pulled out of the Warbird by a zombie.
Oz (narrating): Three platoons were sent in to cage their new pet. Two came back in body bags. An acceptable loss by Atlas standards.
The scene then shifts to the Atlas research facility, at night. Oz is seen doing clean up duty.
Oz (narrating): Then they brought them here... for research. Gotta get a return on your investment.
Oz then notices streaks of blood, coming from several broken glass casings, as well as three dead bodies. The scene zooms in on one of the casings. A hand suddenly appears, and cracks the glass.
Oz (narrating): No one bothered to tell the rest of us.
The scene switches to Lilith, who is working at her desk. An alarm then sounds, drawing Lilith's attention.
Lilith: What the hell? There is no Sub-Level 6.
The monitor in front of Lilith displays "Access Denied".
Lilith: *sighs* Execs do love their secrets.
She begins to type on the virtual keyboard. The screen then says "Access Granted". A second screen to her right then displays security footage, showing a zombie eating an Atlas employee's guts.
Lilith: Oh no.
The zombie notices the security camera, and lunges at it. The scene then switches to Kahn, who is viewing the same footage in his office. He then picks up his phone.
Kahn: You gotta be fucking kidding me. (on phone) Arlene, get me security.
Kahn looks outside, and sees a the second level of a building block in the facility explode.
Kahn: No, all of it!
The scene then switches to Decker, who is helping the Atlas employees evacuate.
Decker: This is a Code 3 evacuation. Remember the drill! Stay together, and try to-
Decker then sees the zombie horde coming toward him.
Decker: Son of a bitch!
Decker then makes a run for his life as the zombies swarm in. The scene shifts to a view of the facility, with explosions across all floors. Zombies are shown running amok, outnumbering the remaining Atlas operatives.
Oz (narrating): No warning... No backup...
A Warbird arrives at the landing zone, but is then attacked by multiple zombies.
Warbird Operator: Approaching the landing zone and-
Oz (narrating): No one left...
Warbird Operator: What the hell!?! Get it off! Get it-AGGGHHHHH!!!
The Warbird then crash-lands as Oz, Lilith, Decker and Kahn arrive for their evacuation.
Oz (narrating): ...But us.
The camera then zooms in on Oz.
Oz: I fucking hate the Atlas Corporation.
The four survivors prepare their pistols.