The way I see it, he broke the rules, and shouldn't expect anything differently.
Also, if I were him, I would've let the robber just take whatever the hell he wanted. To me, that job isn't worth putting myself in harm's way to try to stop a robbery. IMO, he's lucky he caught the robber off guard and wasn't shot in the process of trying to play hero.
I have a mild interest in guns. Actually, I think the clinical term is "obsession," but that makes me sound like some kind of gun-nut. Which is fair, since I am.
Wastin' away my future children's inheritance one box of ammo, range fee, and bottle of Hoppe's #9 at a time.