I find it disturbing (but I'll get over it) that the attacker was carrying hollowpoints. That goes against the stereotype that I wish I could adopt - that criminals are thoughtless and ill prepared. Well, in some areas of life they are thoughtless but that's a different matter.
His girlfriend helped him get the gun - I'm guessing that's a straw purchase, and she probably received some help at the store to purchase effective rounds for it.
So while I can almost hear someone saying "see! if the girlfriend couldn't purchase the gun then the boyfriend wouldn't have got it". but where there's a will there's a way and someone bent on breaking the law has wider boundaries / resources to draw on. About carry licenses: the attacker was illegally carrying the firearm (if it's true he was an ex-con) and the defender was doing so legally. This is an argument for licensed carry. If concealed firearm licenses were banned the attacker could have used a large knife (also illegal to carry in some places) while the defender might only have folding pocket knife...so long as it wasn't beyond 2.5 or 3 inches or whatever the magic number is.
Sorry to get off topic, preaching to the choir I know. That robber seemed to have thought it through, commanding everyone to lay down on their stomach which would hamper physical movement and vision. Just a bit unsettling.