thing happening with the body does to react to the altitude, the lack of oxygen, and the low temperature? >> both. those are adaptive mechanisms that we've all adjusted to to keep us alive in those extreme states. >> so as you say, seems to be a medical miracle that he survived this and walked off the plane. it's not the first time we've heard of people surviving these extreme conditions, a couple of examples that i wanted to get your take on and how it actually worked. a woman, marcia page, survived a skiing accident. fell off a 65-foot cliff. she laid in the snow for 45 minutes at 6,000 feet. her body temperature dropped to 90 degrees. when is it dangerous? how low -- when your body temperature reaches at what point is it going to be a problem? >> that's what's amazing about this case. we don't know exactly how low his body temperature got. >> great point. >> in these cases we do. we don't have an answer to exactly how low each individual's body temperature can go before these states become deadly.