If this is in fact a hack, I hate to have to report you Dimitri since you've always been good with me - but at the end of the day a hack is a hack and no one should be exempt,
That looks more like a mouse/keyboard player random shotting, in fact i've known that player is m/k.
It would be suspicious if he had headshot'd you in that video with that crazy movements. But he didn't even kill you with sniper.