Actually the people filming the documentary were not part of the disaster. The two expeditions that got in trouble had no cameras. They were commercial "danger safari" types where experienced climbers take a bunch of adventurous rich guys to the top of Everest. Because they were competing for clients both leaders went up when the weather was changing, against their better judgement. A late snowstorm stranded the 2 groups on the top of the mountain and iirc 5 died, including both greedy expedition leaders.

The Discovery team had refused to go up with the bad weather and saved many lives at the time, by helping the survivors of the two ill fated groups, sharing all they had: food, tents, oxygen, medicines, radio, etc... with them.

The IMAX movie shows that the 3 guys of the Discovery expedition had to brave gale force winds to get one of the sickest survivors in a place where a helicopter could reach him and take him to a hospital. Coming down ice crevasses with a barely conscious person (the guy) was no picnic and saved that man's life. But risked 4 other lives: The 3 climbers who carried him on their backs and the helicopter pilot who flew a lot higher than anyone thought possible, including the helicopter manufacturer.

There's a book and a movie made about the 2 expeditions, as mentioned above, the name of the book and the movie is "Into Thin Air". I recommend it. And the IMAX movie made about the Discovery climb is great too!