Fred wouldn't stop running, eventually barreling into a bathroom where he locked the door. Several sniffles and sobs could be heard across the length of Mikhails pleas, eventually quieted after you can assume he slumped against the door, "leave me alone," he would say, "please just leave me alone. I'll come out later. I promise," with that he would sit quietly behind the door.

From this hall lead many other pathways throughout the compound, some rooms for stock, others repurposed. There were guard quarters and altar rooms for the cultists. Excersice rooms, break rooms, torture and surgery rooms, a med bay, a large kitchen and mess hall, the large showers and bathrooms where Sarah might have left from, and a communications room. Siegfried mentioned some of the guards staying behind, their lives and memories almost completely gone, same as the cultists. Siegfried himself is around here somewhere. 

Fred mentioned a grave site, as more than a few may have passed in these trials. Rob is buried there. There is also the loading dock where the escape was supposed to take place, and of course the pit with it's machine.