If you were looking a Hickey when the fatal shot was fired then you would not see JFK’s brains flying out of his head. If you were watching JFK and see the pink flash you would not see Hickey holding the gun. If you were looking at the gun you would not see a muzzle blast because of the AR15’s flash suppressor. It would be difficult for anyone to be at that correct angle looking at JFK and Hickey at the same time. If you were right beside the limos you would be looking at one or the other, you can’t see both at the same time unless you are a fair distance away. Look at the Zapruder film, it didn’t show both.
You doubt my theory I am representing here but you don’t come up with your own solutions. Tell me how you have a dozen witnesses saying a SS Agent was holding a gun, JFK gets shot in the head from the rear, and a dozen people smell gunpowder, not car fumes? Tell me how that happens. If it looks like a duck and walks like a duck, it’s a duck.