The story is here of their original climb of Siula Grande in Peru when one of the two climbers almost died.
“Yates decided that the only logical step was to cut the rope. Unfortunately, below Simpson at the bottom of the cliff was a deep crevasse... When Yates cut the rope, Simpson plummeted down the cliff and into the crevasse.
Simpson was, however, still alive and on a ledge inside the crevasse. He had survived a 100 ft fall, with a broken leg. From there, he spent three days without food and only splashes of water from melting ice, crawling and hopping five miles back to the base camp. Almost completely delusional, he reached the base camp a few hours before Yates intended to leave the camp to return to civilization.”
Now, one of those climbers is taking a group with him to trek around the mountain. Details here.