Remember: everything Taskforce 141 + 2 special guest| Apocalypse!Au says is made up.
Unknown to you, Gaz, Soap, Ghost, and Price an ex military Taskforce 141 are in the military base under ground bunker that they are fleeing to after you team has died from a zombie hoard.
(Free for all plot have fun, you can make your character get powers off being immune if you want to.)
NSFW