I remember this same thing happened at a subway station (or maybe it was on a subway car). Not sure where. But the cops were making mass arrests, and had everybody on the ground. One of the suspects wasn't 100% cooperating, and the cop (a man this time) pulled his Glock and shot him square in the chest. He thought he was holding his Taser. I don't think that cop was even arrested. I could be wrong, but I remember no follow up report of him being arrested. The shooting was a viral video that we discussed here. Might have been ten years ago.