I'm curious, if you were the cop and had thought the man had stolen something, what would you have done? I wonder what SOP is for that police force?
I would have thought that the cop would identify himself, put his hand into his sweater and gripped his weapon, instruct the man to put his hands on the counter and ask questions.
I have greater faith that the cop would be able to manage the use of his weapon, than the scenario if he only verbally confronted the man and the man had a hidden weapon or quickly attacked. Sure, scary for the man and the clerk, but the cop never pointed the gun, kept his finger off the trigger, nor became overly aggressive. He definitely could have done a better job identifying himself.