As far as I am aware, the ravine area had never been investigated as a crime scenery/area by the second search party.
By the way, this had been an awful lot of work, removing some four meters high snow by hand over a large area.
The way the den and the four group members had been found on the floor of the ravine near the snow, suggest that the snow conditions had been very favourable for the group members (at the end of January).
If this had been the case, group members descending to the ravine had not needed to dig in the snow - or use tools like ace-axes - to have access the stream in the ravine for fetching running water.
All in all the stream in the ravine had been very easily accessible for fetching running water at the date when the group members had set up the tent area.
The obvious way to carry sufficient water back to the tent site is by hand in waterbottles or in buckets.
If I may guess who had descended to the ravine area to fetch water is using the photos by the camear as a hint:
- three group members are visible on the photos taken on the last days of the group as a subgroup, see the next 'loose photo':

On this photo, Zinaida is passing by in the front while Semyon invited her to join the three group member: the way she smiles on other photos showing the four, shows that she had joined on this portrait of the four with reluctancy. Based in body language visible on photos from the cameras, I have the impression that Semyon and Zinaida had not been natural friends during the tour.
So based on teh photos made by the cameras, I guess that Lyudmila, Semyon and Thibo had descended to the ravine in order to fetch running water.
The post-mortem reports provide another hind for estimating who had descended to the ravine:
- Only Lyudmila and Semyon had broken ribcages
- Thibo had a bad partly crushed skull at the side of his head.
In case a blast wave had caused this injuries, these three group members had been standing in the ravine area:
- Lyudmila and Semyon on the floor of the ravine, because the shape of the ravine operates as a concave lense for a pressure wave from a blast high in the air. The shape of the ravine causes that the pressure on the two ribcages had been twice the value of the original pressure wave descending to the ground.
- Thibo had been standing on top of the ravine: the convex top diverts the original pressure causing a considerable lower reflection: he had been mainly hit by the original pressure, only half the pressure that Lyudmila and Semyon had have on their ribcage. Unconscious, Thibo had fallen sideways from the top to the bottom of the ravine: his head had hit a round stone in/near the stream.
In the theory that I have drafted, Zinaida had spent the night in the tent with Rustem - hint: they had been often on duty together according to their diaries. The next day, Zinaida and Rustem had placed the bodies of the other group members in the postures as found by the two search parties. While doing so in the ravine, Rustem had fallen and as a result had a crack in his skull. On the way back to the tent, Rustem had suddenly collapsed by brain damage: Zinaida had waited next to him until it had been obvious - that he was dead; she had turned him until his face was not visible anymore. At that time - somewhere 9 pm the next day, her hypothermia had progressed that she had been able to walk a small distance home - the tent in this case.