Because of my extensive gym training, I'm able to get myself into some incredibly tight spaces. One such space involved the underneath of a set of steps that were about one foot high, with about four feet by one foot "crawl space" to work with. I had to really exhale the air out of my lungs to get in but I stayed in and was unfound for over half an hour. I was hidden so long that everyone assumed that I'd been found but was elsewhere, until I emerged much to the surprise of everyone else.