My first instinct is to grab the shotgun and hold my ground. Perhaps risk using one of the slugs as a warning shot to chase off the pursuers. If I succeed, I get three guns instead of one, plus a possibly-usable vehicle, and can later barter away the other two guns if I need to. But since all of the options are forcing me to run, I shall pick the most portable weapon and skedaddle.
Why does it look like all of the gun photos were taken on the same motel room's ugly carpet?