Down the Rabbit Hole.
“There is no real ending. It’s just the place where you stop the story.”
― Frank Herbert
Something does not add up here, how did a thief get a gun in NY city, I thought there were laws against that, maybe they need more laws the thugs will obey. Second of all how come the store clerk is not being charged with assault, they don't have a "stand your ground" law there. Nothing makes sense any more.
That occurred to me too. Since there is a law against handguns in that place, it is theoretically impossible for them to exist there. And clearly, as you say, the clerk was completely in the wrong because he chased off the would be bandit. A moral person would simply have allowed himself to be robbed. There is much here that warrants further scrutiny.