"K2: The Savage Mountain", by Charles Houston. An account of the 1953 American expedition to K2, in which the party is pinned at 26,000 ft for quite a few days by a severe storm. One team member, Art Gilkey, develops thrombophlebitis in both legs and later an embolism in his lung as a result of many days spent immobile in a tent during the storm, combined with the usual thickening of the blood due to increased hemoglobin produced by the body to compensate for lack of oxygen at altitude. While his teammates are starting the process of lowering him over thousands of feet of technical terrain, Gilkey disappears over a cliff. The official explanation is that an avalanche swept him away while his teammates were preparing to lower him further and tending to other injured party members. It's now widely accepted that Gilkey figured out his odds of survival, factored in the odds for anyone who stuck around and tried to help him, and launched himself over the cliff.