There could been a second den that wasn't discovered.
A slab slide could explain the rav4 injury profile (2 chests, 1skull and possibly Rustem) but i think pushed to the floor fits better.
I don't think Zina or Igor got down the slope.
So Zina and Igor did not make it down the slope. But others who were poorly dressed did make it down? Why? Why did some who were poorly dressed make it down but others did not? As far as I know, Zina and Igor had no disabilities that would prevent them from doing what the others did.
The state of dress is irrelevant to completing the descent.
First some facts :-- Igor clearly died of hypothermia showing the classic sign of max bladder volume. He has a strange wound on his left cheek with parallel lines and a right angle. YuriK has a group of similar wounds on his left thigh. Igor's lips are encrusted with blood. It's my understanding that death from hypothermia takes a significant length of time = hours.
- Zina was found with her "face in blood". The morgue photo shows a third to half of her face covered in sores which the autopsy records as "abrasions". N.b. the photo shows no direction for these abrasions which include her right eyelid. Also she has a bleeding bruise on her waist. Her corneas are stated as "opaque". She has a gash on her hand.
Now some simple conjecture.
Whatever forced them to flee the tent impacted some of them shortly afterwards on the descent. Zina and Igor could have been blinded/poisoned or suffering from chemical inhalation (e.g. nitric acid), YuriK received a third degree burn and shouldn't have made it down but was assisted by his best buddy, Yuri D. Both of them demonstrating asymmetric frostbite relative to the rest of the group.
I love this forum because the posts here by very intelligent people remind me of information I have not added to my theory.
You have reminded me of Zina's bleeding bruise on her waist. This helps confirm my theory.
I believe the hikers thought there was an avalanche due to a terrible storm on Mount Kholat Syakhl. This storm had extreme winds which carried snow down on their tent. This snow could not be distinguished from the start of an avalanche.
Tibo and Zolotaryov were outside dressed warmly and fixing/inspecting the tent due to high wind damage. Dyatlov communicated with them through slits he created in the tent and he would use a flashlight from time to time to see out the slits. He dropped this flashlight in the panic of the "avalanche" outside the tent where it was later found. Most of the snow later blew away during the three weeks it took for rescuers to arrive. Some snow remained on the tent with Igor's switched-off flashlight.
All nine made it down to the cedar tree without injury. Two died at the cedar tree. Seven went to a ravine and dug a den. The den triggered a collapse of a large amount of snow. All seven hikers ran but six were caught up in the snow collapse and suffered injuries. Four died, but Slobodin and (Zina) Kolmogorova escaped with just injuries. Dyatlov was least injured.
The three survivors saw no other choice but to go back to the tent area. They froze to death.