There was a thread by a man who claimed his late father confessed shortly before death to flying a hunting group out there at night and they ended up hunting the hikers after Rustem floored a hunter for suggesting the girls join the hunters inside their tent. The hikers went on to fall like flies in the cold, while the hunters survived, and had time to sweep 1079 for tracks and shell casings. An artifact, a hikers knife, had been kept in a box under the father's bed for decades. He couldn't go public as his mother was still alive, but invited applications for the film rights to an e-mail address.
I have to confess I have a hard time imagining Rustem as a he-man, a hang loose long distance runner, physically resilient, yes. It can only be based on a subjective opinion, but I believe I've studied the photo's more than most and from his kinesics throughout his life and on this hike he just doesn't look the type to be aggressive. The only reference there seems to be suggesting he 'knew how to handle himself' is the story of him and his father on a hike together in what is described as though it was bandit country.
Because I believe the hikers may have been poisoned and suffered seizures, I could suggest that Rustem collapsed face down into the snow, and suffered an earlier seizure which caused a head injury. Falling onto your muzzle, even in snow, without breaking your fall could cause facial bruising. Do it onto a hard floor and it would break your nose. Convulsing on the ground, repeatedly grinding your face into the snow, could cause all manner of scratches. Some hikers had them to their upper eyelids, and Igor's left underarm was covered in scratches.
As an example, the British popstar Professor Green has recently had another epileptic fit and fell face forward alone at home blacking his eye and grinding grazes into his cheek from several minutes of convulsions. It's taken him a while to recover. A previous fit saw him fracture 3 vertebrae in his neck.