Killing Floor/KF-BioticsLab

Defensive areas
In the lower area in Sector B observatory, you should have a small loop with two double doors. Weld the one near the trader, and wait at the other entrance. Enemies will walk through one door, allowing an easy defence against the incoming monsters.

Trader locations

 * Lower floor, after staircase on left-side of map.
 * Lower floor, in Sector B observatory area.
 * Upper floor, on right-side of map behind lab.