I did door-to-door canvassing for political campaigns and nonprofits in college - if someone answered the door with a gun in their hand, I’d be terrified. Of course, my inner snarky bastard is inclined to concede that I might deserve it - but, well, I probably didn’t; I was a dumb kid, sometimes trying to make a few bucks, sometimes just helping out friends for free. And being on foot in the suburbs, with all your friends blocks away, means you really don’t want anything scary to happen when you knock on a door.
So, what would I do? Probably mutter some hasty apology, then run like hell.