We managed to gather most of the infected into a single, gigantic horde. Now we can get rid of them in a single assault!
The only exit is the passage we left out, closed with reinforced, electrical doors. We need to gather enough fuel to start the generators, open these doors, and get out!
Based on a Mission by Elwyn Pidoux-Le Pessec, this is a scenario for Zombicide: 2nd Edition.