Overall, extremely odd. Nothing 'fits'.
Bone damage, but no soft tissue damage. Overpressure, maybe, but there would be massive hemoraging. If blood vessels in their eyes bust or they had massive bruising, I'd say it was some kind of thermobaric weapon. That and secondary effects from such weapons are bloody obvious as they tend to be destructive.
Whatever it was, it was scary enough to send eight Russians running away from prepared shelter into the night with a likely temperature of -10 F and a nasty windchill. That is certain death, and as experienced Ural hikers they knew this. What is more frightening than certain death by hypothermia? Drugs would be the obvious answer, but I would think that they did a tox scan on the corpses. Drugged up college kids wouldn't be a state secret, even in 1950's USSR. Wouldn't explain the radiation, however. Rads, but no obvious source. It had to come from somewhere. Why would it be on the corpses and equipment, but not the surrounding area?
I read the skeptics' page. Their opinion is 'weapons testing' and scoff at the oddity of the situation. Uhm, yea, no weapon exists then or now matches the description of what happened. Any single aspect has a possible answer, but none fit with the rest of the facts. My 'rational guess' would be that something was omitted or removed from official records.
With the details as they are, I'd personally chalk it up as "Weird things happen that are beyond our understanding." There are a lot of strange things out there in the world.