While the team waits for Murphy to finish peeing during a pit stop, they discuss the distinct possibility of his one day turning into a full-blown Z. It's reasonable to assume that this transformation would make his personality even more disagreeable.
The team takes a tour with Charlie's old colleague, Major Wiilliams, who tells them the compound is entirely weapon-free. In a zombie apocalypse, that might not seem like the best approach, but so far it's worked.
Reverend Jacob captures the team and tells them they can either become zombies or help make more zombies as part of his insane "Resurrection" plan. Say what you will about the man, at least he's got passion.