I wasn't aware of the controversy around Doug Copp, but the triangle of life idea seems to me to have only a limited or very particular application in real life. As architects can tell you, we don't often have buildings that pancake in the US. In most places, you can be hit by falling ceilings and debris, but entire floors pancaking should be exceedingly rare. But this might be situational: I currently work on the second (top) floor of a building at some risk of collapse, but if it does I am at least on top of the lower floor and the parking area. When I move to the first floor next month, I'll have the second floor above me to consider. Either way, the best option to shelter is duck cover and hold below my work desk, and hope for the best. When I'm on the first floor, I have to hope that any collapse leaves a local void around my desk.

I can say that in CERT training and real life, alot of rescues come from these voids, and they train you to look for them.