So, I am absolutely not defending the shooting itself, but everything I have read about this is that he definitely tried to remove himself from the situation but the “prankster” followed him and continued to harass him.
And to make things worse, the so called prankster had already been kicked out of the mall the day before and came back and was specifically trying to avoid security.
So yea, shooting was almost certainly an overreaction, but I do then wonder how exactly you are supposed to deal with something like this when this asshole won’t listen and won’t let you leave.