Well, no, maybe, I don't know, but how can "large surface area impact" be human inflicted? Maybe it's possible somehow, I just can't think of how.
What has a large surface area on Kholat Syakhl?
- the ground
- large trees
- what else? a failed rocket, satellite or helicopter?
- a snow slab?
It's very unlikely for anything airborne to land exactly where they were sleeping - you are right, the injuries indicate they were laid down when those happened.
I think even these few options have issues, if something large fell on them whatever it is, who removed them from under it and how?
That leaves two options really, snow and falling from a height. Maybe my imagination is too tame.