Ok. I don't think one can conclude trajectory without points of reference ie A. Muzzle B. Wall straight line from A to B. That said I believe the event was staged due to the SOUND & SIGHT of blast & recoil. The load of powder in a blank round sounds less significant than one with a projectile. Think fire cracker compared to flash bang. The amount of powder use in a load with a projectile has much more powder than a round with cardboard or paper holding it in therfore the BANG or BLAST was consistent with low powder load. This would also be consistent with the lack of recoil of the pistol being held by the "CP" displayed in video.
Infact watch the motor & facial reflexes of all in the video when the shot goes of. Marked lack of flinch or dodging by those hearing the "shot". Someone has to yell SHOTS FIRED as to cue the behavior. If anyone has ever shot a weapon or has been surprised by a real shot fired can relate.