In a post several days ago, I stated that a "psychotic reaction" explanation was possible but that the evidence didn't seem to suggest it was likely. Why? They seem to have secured the tent, calmly walked down to the tree line, and did rational things in order to survive the night. Now I think this needs to be reconsidered, not for most of the incident but mainly what led up to and included cutting the tent (for the scenario where that is relevant). One thing I find frustrating is how important that tent likely is to understanding the DPI and how nobody seems to explain what happened to it, or the inspection/assessment of the tent was done improperly. On this page, for example, it seems that there's no strong conclusion one can come to about it:https://dyatlovpass.com/1959-search
However, when it was pitched in the investigation area, it appears to have been torn to shreds. Did the rescuers do most of this? If so, how can we tell? We are also told there are a bunch of attempted cuts that didn't go through. This certainly could be consistent with some sort of "psychotic reaction" incident, though it's also consistent with a lot of the "far out" explanations, such as a UFO craft hovering above or poisoning of some kind. But let's stick with the more mundane possibilities here (the others have been discussed at length and I have nothing to add to those). For example, from the diaries, we get the sense that there was a lot of internal dissension, and that some thought Igor was acting like a tyrant. We know that Igor, and one or more others, had an unusually large amount of urine in his body at the time of death, but there were a couple of frozen urine puddles outside the tent most likely from Semyon and Nikolay. Here we are told they likely were outisde when the "event" occurred:https://dyatlovpass.com/death?flp=1#Kolevatov
So, one obvious scenario is that Igor told them not to go outside the tent because it was too cold or dangerous in other ways too (and that they'd have to hold their urine that night), but they went outside anyway, and he woke up while they were outside. At this point a number of things may have occurred, but again, if we knew more about that tent it would perhaps point us in the right direction here. For example, Semyon or Nikolay may have been trying to get back into the tent quickly, and fell onto the pole or ski holding it up on the side. This may have angered Igor so much that he cut a hole in the side, wanting to get out and yell at them, or worse. Or could Semyon and Nikolay gotten drunk, fell on the side of the tent, collapsing it, and that panicked the others, at least one of whom cut the tent open. Or Semyon or Nikolay could have been so angry at Igor yelling at them about being outside that he pushed over the pole/ski, collapsing the tent, and telling him he wasn't their king, which led to Igor being so angry he cut his way out to get at them.
This would explain why there were two sets of footprints going down to the tree line, why some (including Igor) had hand injuries consistent with a fist fight, why at least two different plans were initiated once they got down to the tree line, and why after the "two Yuris" apparently died first, the remaining seven went in different directions literally. I think the best thing to do is to try and recreate, exactly, the two tents sewn together and put that up on the mountainside, in the same place and under the same weather conditions, with nine volunteers in there, to see what happens, but until then even the strange urine situation should not be entirely dismissed as possibly being the spark that lit the fuse, and the explanation being of the "psychotic reaction" variety.