Before he took the older men onto the ice pack, he showed them the film of the fellow who suffered that frost bite in order to impress on them how important it was to button/zip all layers after urinating. It takes effort in way below freezing to get all that insulation back where it belongs and the male makes the mistake of thinking it will be okay to just have the layers there and not fasten them properly and the frost bite happens very quickly. Not much of that piece of anatomy is attached to the body so it can freeze very rapidly and once that happens the person has to get off the ice as quickly as possible for surgical care.
The medical man was there to watch for frost bite anywhere on the men.
Once Wayne made that first three month film on the ice pack, from then on when any company wanted to make a film in that type severe cold, they called Wayne to do it - that’s why he was the one to make the two Siberian films. There are special precautions that have to be taken for a film camera to work in that severe cold so he also instructs other film makers how to preserve the camera so it will work.
Your son has my admiration. No way I would be adventersome enough to visit those extreme temperatures. My joints and bones ache just thinking about it!