Not a coincidence at all. They are both reacting to the same shot. The zfilm does not tell you that JBC is reacting to being hit by it.
Not it doesn't. You have to apply common sense to figure that part out.
The evidence tells you that JBC is reacting to hearing it.
No, it tells YOU that. People with common sense have figured out his reaction is to being shot.
You have some of the worst analytical skills of anybody I have encountered on the subject of JFKA, LN or CT.