Tom...

Based on our experiment, you don't have to get very cold at all to lose rational thinking. Our subject was at 97.2 for at most 15 minutes, possibly even less. We listened to his declining judgement for several minutes before we realized that he wasn't just being heroic because it was his job. I can easily see how someone could power through the discomfort in an effort to "escape" and then start to think that the situation isn't as bad as they thought as they start to get colder and feel less uncomfortable.

MNS