I ordinarily discourage unarmed people taking on someone with a gun, but when the mugger got the money and ordered the guy out of the car anyway, I think it was becoming more than a robbery attempt.
Definitely an escalating event, likely to end up with somebody being shot. Fortunately, it was the right person.
Play stupid games, win stupid prizes. Hey, wait a minute I thought people were not allowed to carry handguns in Chicago!? How can this happen?
People are also not allowed to speed, talk on their cell phones while driving in Chicago, etc., but law enforcement regularly do all of these things (along with most of the civilians). Is anyone surprised?