I was running through the Abandoned assembly with a friend today, and we both found a spot where, when you walked over it, you would automatically die, no matter your health. It was just at the entrance to the Long straight-away at 1:37 in this video: http://www.youtube.com/watch?v=RLk7UAIaqqE (Youtube was the only way I could think to show where it was precisely..sorry if that's annoying). Needless to say, we were forced to return to Haven, as there was no other way to progress in the level. Thanks.