I think Blanks usually have some sort of fiber packing but you have to be really close to do damage like holding to your head. 2 people hit and one killed is unusual. A real round in the gun by mistake ?
That’s what I’m thinking, point right at the camera, shoot and get the cinematographer and someone behind them. Who knows at this point, but if it was the cinematographer and director you have to think a scene. I wonder if it was multiple shots.
FReegards