Haston and Scott sat out a night at roughly 8,750 metres with no tent, no stove, no sleeping bags and, by then, no oxygen. They'd summited late in the day, too late to get down, so they scraped out a hole just below the South Summit and waited for light. That was 1975, and the Southwest Face, the first time the mountain went to anyone by a face rather than a ridge.
Before any of that, the carrying. Camp 6, somewhere above 8,200 metres, doesn't stock itself: the Sherpa team hauled oxygen sets, rope, fuel and food up the fixed lines hung all the way from the Western Cwm. Ang Phurba, Pertemba Sherpa and the rest of them, load after load, on a face that holds no snow and drops everything on you. Nick Estcourt and Tut Braithwaite had already forced the Rock Band at about 8,200 m, which is the bit everyone had failed on. Bonington led it. Pertemba reached the summit himself two days after Haston and Scott, with Peter Boardman.
At that height the blood has thickened and the body pulls circulation in to the core, so fingers and toes are the first thing it's willing to sacrifice. Haston and Scott had a still night and no wind, which is most of why they came down with their hands — Scott got frostnip and not much more. Extraordinary luck, on top of the fitness.
Alpine choughs work those camps up to around 8,000 metres, black birds on the snow going through anything left unzipped. No oxygen sets, no fixed rope, and not the least bit impressed by the people doing the hauling.