Nah its really early on in the game, about the third level
Its where you can get that nail gun out of the caravan, where the bloke is having a dump. I saved it before that point and once I turn the switch off at the other end I get completly fuc>ked over.
I think the camera angles are alittle anoying at times, that kinda ruins it for me as sometimes its hard to see whats going on.