Hope everyone is enjoying the winter holidays.
Maybe another scenario is worth contemplating, more straightforward than many I have read. The night lights, most likely military tests - parachute flares and/or mines - started abruptly. The sleeping hikers would have been extremely alarmed at the noise and lights inside their tent with no external view and the exit secured, so they slashed the tent to see what was happening - some of the cuts were only a few centimetres long. Seeing nearby and violent flashes and explosions it was time to leave in a hurry - aside from the shock, the explosions could well have been thought as a precursor to an attack or other imminent danger on the ground, where they camped. So they slashed their way out of the sealed tent, and they started to make their way towards the nearest cover. Initially this was in sufficient panic that they left much of their survival equipment, clothing and footwear behind. Then the pyrotechnics stopped at least for a while, and they regrouped and continued at a more measured pace in pain caused by the rocky snow covered terrain beneath their inadequately covered feet. After that, they reached the point in their descent where, away from the lee of the ridge, the snow would cover their tracks over the coming weeks - that would also apply for the tracks of the three who would subsequently try to return to the tent. Their tracks in the first few hundred meters survived until the rescuers arrived because they were sheltered by the ridge and there was no fresh snowfall, the very bad weather in 1 February having passed on.
Reaching the forest all nine hikers managed to start their fire after some time. Although out of sight from any threat to the tent, the group was by now suffering severe frostbite and hypothermia. The worst afflicted attempted to gain warmth from the fire (and suffered skin burns while doing so), whilst the less afflicted started to look for better shelter. Many reports say the ravine in which four of the hikers were found under 4m of snow was 75m away from the cedar tree.
The seven hikers found the nearby ravine and judged it suitable for an emergency shelter, at least until any danger at the tent could be discounted, probably at dawn. For the same reasons as that judgement, a family of brown bears had decided the same thing at the start of winter. Bears do not hibernate through winter - their body temperature does not drop to match their surroundings where they cannot be revived. Instead, they are in a state of torpor, and awaken quickly if disturbed. So could it be that the hikers disturbed a family of bears themselves sheltering from winter in the nearby ravine, and that the adult bears would have reacted violently to the sudden and immediate perceived threat to their family? The bears would probably already have had their winter torpor disturbed by the pyrotechnics, and so would have reacted to protect their family.
If so, the subsequent violence may explain the injuries to the four found in the ravine (augmented by the water flow over soft tissue in one or two cases), and also the bruised knuckles, minor skull fracture and skin wounds on the others. The 5m or so of lost branches at the base of the cedar tree could have been a desperate attempt by one or two hikers to avoid the attacking bears. By the time this happened, the two most afflicted by hypothermia next to the fire had died, so were no threat to the bears and were left untouched.
The remaining three hikers managed to escape the forest to attempt to return to the tent, the pyrotechnics having long since stopped. They were not together as again they were leaving in a state of panic at what had happened in the forest, and because of the threat of the bears’ persuit. At different points, they expired from exhaustion, shock and hypothermia. Their tracks from the forest were covered by drift snow before the first rescuers arrived.
I’m open to corrections on many points (particularly the winter behaviour of bears), but I think the facts are right and the suppositions regarding the military tests and bears leave less unexplained than some other theories. I don’t subscribe to the ultrasound theory - none of the many subsequent visitors have recorded any instance of it there. I also discount the animal /yeti threats due to the lack of non-human footprints near the tent as well as the tent and its contents not being further damaged. The topography reportedly renders an avalanche highly unlikely. I don’t think the stove was to blame as the tent wasn’t burned, and fumes alone would have been unlikely alone to prompt a barefoot escape to the forest.