The diaries suggest Zina was upset by Igor's behavior and also the two women alluded to something happening that was inappropriate (apparently not involving Igor) being done by one or more of the men, so this is a reasonable general notion to investigate. However, the dispute (s) that night, the evidence suggests, was about how to survive (avoiding hypothermia), in that there was a "den" and a fire (though those could be part of one plan, which would be to warm up while the two better dressed guys dug out the den), and then apparently after the "two Yuris" died, the group split up. I think a good possibility here is that Zina was angry at Igor and decided to go back to the tent after one or both Yuris died, then Slobodin went after her, but fell, struck his head, and went unconsious, so then Igor went after her (to tell her she couldn't survive up there). However, the original plan may have been for a few to go back after they were sufficiently warmed up, which would explain why one of the two flashlights was placed on top of the tent after it was secured. If the three were going back to the tent as a group, though, I think there would be more evidence that they tried to stay together or help each other, and if they were so close to hypothermia, it would make sense to go huddle with the other four in the den. Thus, I think Zina may have headed back to the tent as soon as she saw one of the Yuris die, or when she saw the others begin to take clothing off of one or both Yuris. This would explain why the "ravine 4" had clothing from the two Yuris but the other three did not (or Igor just had a vest, which would presumably be fairly easy to take off a dead body and put on). I think Igor may have been helping dig out the den with some of the others, then when he goes back to the fire he sees that the fire is out, the two Yuris are dead, and Zina and Slobodin are going back towards the tent, so he goes after them (this would explain why he was quite a distance from her and not that close to Slobodin either; he should be closer to her if Slobodin was injured, but he likely started out towards the tent a lot later than either of them).