bb_derelict_lab addon

You and a handful of other civilians have been dropped off at a seemingly small military base, at least above ground. Below the ground is an expansive military installation where research on the undead had been going on. Recently, the base had been compromised. The security guards and solders are doing their best to fend off the zombies and evacuate anyone else still alive in the base, but they still need to recover the research that had been going on down there. Since they are spread thin, you and a few others volunteered to recover the research materials.