In reply to thermal_t: He is lucky to survive: his respiratory rate - breaths per minute - rises from 24/min at 2mins 20 sec to 55 minutes per/min at 5:20. I believe this is due to the snow compressing his chest, and possibly shifting slightly as it settles. 55/min is very fast indeed. he is being forced to take small shallow breaths as he cannot expand his chest enough, and it's worsening fast.
Also he becomes more distressed when his mates move away for a second or two - he's not sure he's going to be able to continue to breathe and is panicking. They think he's ok as they have cleared his face but his chest is still compressed.
they did incredibly well: it's not what you do, it's who you're with!