I may not have noticed the chest spawned in a room. I swore it was in the middle of an intersection. But it was dark as hell so I may not be correct. After getting the chest and exploring more, we noticed the plate. At first I assumed it was one of the 5 plates. But then when everyone ran back to our original plates, the 6th man (who was looking for a door to unlock originally in the group) was on that plate we had just discovered. So at the end, all six of us were on plates. But, no noises, no drumming, no nothing. :/