When faced with an armed robber while you’re unarmed with a firearm yourself, things can get hairy. The guy in the video below is actually shot in the hand by the robber when he tells him that he has no money to give.
The robber didn’t like the response, so that’s why he shot the guy. This turned the clerk into a sort of hulk, and he went after the armed robber.
Luckily he wasn’t shot again, and he was able to send the robbers running after he literally picked up the lottery machine and threw it towards them.
John makes a lot of good points here, and they should all be taken into consideration when you play through scenarios in your head, and of course when you train.