Seems like there's more overlap to this hypothetical scenario than bab or jgvol are giving it credit for.
It's hard to imagine a scenario where people were protesting to the point of crowding my car so that I couldn't move, and I didn't feel unsafe. I just don't think there is such a thing as a safe mob once it gets to that point.
I don't want to hurt people. I'm against it, up to a pretty high threshold.
People show up in my front yard causing legit trouble, I'm not waiting for them to enter the house. They riot to the point of shutting my car down, I doubt there's much I could do about it and I'd probably be screwed, but I'd probably be justified in getting away from them however I can.