kay, well i was playing on nacht today and i noticed that there are war helmets lying around, and i thought maybe nacht was included in the back story and there had been people previously there ( like there was on the other maps ). I think that peter ( the hanging man in shi no numa ) was also at nacht but there was more than just him there. My guess is that the crashed plane outside the building had element 115 on it and they were bringing it to the test facility when they crashed creating zombies and Peter and some more soldiers or marine's were also on it and they went into the building to fight off the zombies but Peter was the only one who survived and had to leave. But hey, thats just what I think!