[null and void]

Yeah, I see it, but whatever hit him would probably be moving too fast to see.

If it were part of the actual bomb, certainly.

If it were, say, a cell phone blown out of the hand of a nearby spectator, maybe not.

In any event, it sure looks like something smacked him.

[PMAS]

It looks like a piece of paper, look next to his left foot as he is laying on the ground toward the end of the video.