He was wearing shorts, was alone, and dark was probably falling by the time he hit the area.

I imagine, for myself, being cold, tired and/or exhausted, maybe somewhat dehydrated after a long day, and alone, and possibly feeling rushed (to join friends? to get down before dark? to get warm? just to end the tedium?). I question the kind of decisions I might make, and the actions I might take, in that situation. I hope I'd have a bivvy sack and headlight with me, so that I'd at least have the option of taking a nap, if I needed one. And the clarity of thought to make good decisions viz whether to rest or push on.

I cannot speculate beyond my own weakness, strengths, experience, skills, equipment, and judgment, to extrapolate what occurred with this gentleman. We don't know this gentleman. We do not know what he had in his day pack. We do not know his friends. We just know that this is a very sad story with a tragic end.