just noticed some really bad cases on biotics lab......now that the U-room kinda sucks, the best place our guys have been able to hold is right at the spawn and the long "T-hallway". if you look in where the main door is (above the stairs), clumps of zeds will just randomly spawn in it even though it's right in the line of sight of the players in the hallway. also in the back room to the right (where everyone breaks the window), they'll randomly spawn in there if there's nobody in sight of the room.....even when you weld the doors shut. actually, one time we welded both the doors in the left room off the hallway and zeds still spawned inside the room and were trapped by the two welded doors....good thing there were 4 pipebombs in there waiting for them 
just random, wierd spawning mechanisms.
just random, wierd spawning mechanisms.