When starting the descent, Lois says "At least the hard part is over." That is a widespread belief but it is erroneous; the descent down a difficult mounting is almost always harder. For one thing, it is more difficult to see where you need to step etc. because your own body is in the way.
Peter suggests everyone strike a funny pose "so when they dig out out bodies, they have a good laugh." The dead are usually not recovered from the dead zone (above 7,000 meters) because it would be too dangerous and exhausting. It is impossible to reach with helicopters, so the bodies would need to be carried down by other climbers who are themselves weakened and slowly dying from oxygen starvation.
Brian's tail is outside his clothing. He would inevitably lose it from frostbite.
Early on, Brian refers to Everest as the world's most dangerous mountain. While Everest is the highest peak, it is not even close to being the most dangerous. K2 and Annapurna both are far more treacherous climbs and most 8000ers except Lhotse are more difficult. The only reason the most people have died while trying to climb Everest is because many more people try, among them lots of amateurs in guided tours, since beside the prestige, it is one of the "easier" climbs, as far as 8000ers can ever be "easy".