I feel bad just watching that dude. One time I took the action tour in the Cango caves in SA. There is a passage. Where you have to breathe out all air and tilt your head to get through. Even if you are just a 70Kg man. When we saw the hole. We asked the little girl who tagged along the tour guide. Are we going in there? Because it looked fkn impossible. When I got stuck I immediately panicked and had to use my iron will to cool down and get out. I simply cannot believe nobody ever got stuck and died there XD