An absolute tragedy but I think it is far too early to judge and more information is needed.
The weather here may be extreme to us generally though many of our forces serve in places with far more extreme weather. Training is done under extreme conditions or how else are they to cope when dropped into a warzone with far more extreme circumstances than weather to cope with.
It's all unknown, the experience, level of training, sufficiency of hydration, how quickly help was maintained, so many things and from both sides.
I was an RAF cadet and we used to use live rounds in shooting practice and competitions, L98 rifles usually and including exercises where we would run with the gun against others in run and shoot conditions.
It was actually the running, not the shooting that got me, I tripped badly in waterlogged field in a run and shoot (partly trying not to get my gun in the mud to slow me down) and ended up in plaster ankle to hip - though I still finished, the drive, not wanting to let team mates down and having intimidating military men running down the field after you screaming at you to carry on is somewhat of an incentive, even if defying common sense!
Before we were allowed anything other than a .22 though we had to learn about the rifle, safety procedures, how to strip it and put it back together and be examined by an outside examiner before we could use it with live rounds.