But how would the shooter know the question was asked, unless the hand signal guys informed him... but he’d be looking at them for the signal, not aiming.
Did they practice it? Because he shoots pretty fast after the question is started. Can you aim such a shot so quickly?
Also, a neck is skinny. Wouldn’t you aim for a wider body part?
Odds are pretty high that the assailant aimed for the head and missed a little low (a few inches). It doesn’t take too long to aim and fire - having attended a couple (just a couple) of rifle matches, the shots start going quickly after the start is announced. Getting in position probably took longer - once you’re laying prone and have a good sight picture, getting relaxed, your breathing right, gently squeezing the trigger.
I don’t know if there was a signal to “go” or if the guy just got settled and then fired his shot.