Definitely sounded like pistol shots. That wasn’t ammunition cooking off, the sound was different. What caught my attention is after the shots, the spectator in front of the camera man started moving away... “I didn’t see nuthin” kind of shuffling away.
As to my knowledge of Russian - the voices in the background shout “Idi otsyuda!”, which means - “Go away”. And the guy who’s filming is saying “Ni huya syebe” which is a vulgar expression, something like “Fu***g hell”, or something like that.
Could be but the shooter would have to be there waiting for the plane to crash. Besides, the autopsies would reveal what happened.