Right, but I guess the question could be asked, as long as he wasn't incapacitated, why didn't he do what was necessary to keep himself alive, such as construct a quick snow shelter?
I argue that his ankle injuries contributed to his demise as one of the combining factors including exposure.
In the balance, a snow shelter is a wind break and an opportunity to rest. Alternately, it requires energy, working arms and hands and it delays covering the mile back to the tent.
Was IRZ's attempt to retain the tent worth dieing for? It is when you have nothing to lose. Surely, those were desperate hours.