Hello there!
I'm new to this forum obviously, but not new to the topic. I stumble upon it every now and then since 10 years and always, it seems to me that guessing what happened then is like playing minesweeper: you can rule out some theories, but on some you have to place a question mark because it seems reasonable, unless you find some details that doesn't match the facts and blows the whole stuff up. The way I see it, the important question is not what killed them (because it was the cold, wasn't it?) but why they went out of the tent.
I sticked with the avalanche-theory a long time, because it seemed to most logical and natural explanation to me. They heard it coming, fled the tent and died somehow.
But then I learned that the area is not known for avalanches, also it doesnt make sense to cut your tent from the inside when you can just use the exit, unless the avalanche would've hit the tent and blocked it. But then, the pictures don't show a tent that was hit by an avalanche. It's snow-covered, but not so much the snow could've blocked the tent. Boom, the mine exploded.
My second guess: a fight broke out somehow. But I don't think that's reasonable, they weren't kids anymore, had a clear destination in a hard environment and had to focus. Also, they wouldnt ALL run outside.
Now, I'm thinking if the cold could've struck them while they were still in the tent. Hypothermia hit, they undressed partly and went outside (for whatever reason).
Sounds stupid, but it's my last take. Don't like all that lightning-rocket-UFO-infrasound stuff.
Is it known if they got their wounds post mortem and if they could've caused by the environment? Broken rips because of the snow squashed a dead body for instance?