Is anyone else experiencing a bug in Zero Hour where the vent that SHOULD be open... isn't? I tried this last night with some friends and know my way through. There is a big open area about half-way through where you are supposed to go down a vent shaft. I've gotten there 3 times now solo, and the grate that covers the vent is laying on the ground, but there is another grate covering the way through. I'm curious to know if others are experiencing this.