I just posted about hypothermia in the Deadly Cold Theory forum, and of course they all died directly of hypothermia, though Luda, at least, apparently would have died from the injuries sustained after falling into the ravine. In that post, I made the point that hypothermia deaths are quite strange, as some die quickly and some go for days in bad weather, also without being dresseed properly. You can read a bunch of these stories in the book, "Off the Wall: Death in Yosemite," but there are plenty of other interesting accounts, for example, that mountain climbers have written. The DP group (or Igor) seems to have been more concerned with securing the tent (from blowing apart or the contents blowing all over the mountainside) than they were of hypothermia, and in just the "Off the Wall" book alone, you can read about a whole bunch of horrible decisions made under similar circumstances (this is also true for most of the major disasters on Everest). In the case of the DPI, they wanted Level 3 certification and Igor may have been sort of teaching the group a lesson because he didn't think they were sewing the two tents together properly (read the diaries). Because the two tents were literally coming apart at the seams during much better weather conditions and with the stove being used, the only reasonable conclusion, IMO, was that this was the crucial mistake, but they still may have been able to survive the night, for instance if they improvised a shelter from the wind (perhaps with a simple wall of snow), using branches to sit or lie on and the blankets for a makeshift tent. However, I have seen on video how the wind comes down the top of that mountain, and it may have been difficult to find any such location that was close enough (a reconstruction might demonstrate this, one way or the other). As to the two Yuris dying first, there are reasons for this, one being that some people have a significant drop in their core body temperature when they stop being physically active, which can lead to hypothermia setting in very quickly. Also, if you sweat your clothes up or if there is snow on them, then you sit in front of a fire, that melts the snow and soaks the clothes, and then the fire goes out, you are in big trouble. Even if it's a robust fire, though, if the wind is still beating down on you, the fire may do little to prevent hypothermia.