I had the exact same reaction to the last scene in Hades. I began looking around trying to find 'someone' that may have supposed to have been there, but did not. I was like okay, maybe the next scene will have this character...go through to the room to realize its the exit. I was kinda let down with that ending. I really hope that is not the way it was supposed to be.
On another note, I agree the scares overall were really below HHN standards to me on Friday night. I saw a lot of scareactors just standing in the open, not doing anything, like you mentioned. I will let the 'scares' go being it was opening night and everyone will need to find what works for their roles. I went back Saturday night and it seemed some of the scareactors started getting into their roles a little more. Hopefully they are even better when I go back this Friday.