[kahljorn]

I don't think you can be fired for giving money to the guy. I'm guessing it was because you were an asshole afterwards(for good reason). If you really wanted to you could probably contact a labor board or something and sue him.
"Hey, you had a gun in your face and gave him the money? I'm going to harass you and cause you post-neardeath emotional distress then fire when you tell me off."