The actor playing the cop says, "No law in here says a dog *can't* shoot people". Is that the part you meant?
The titles say "See Spot gun" (there's no "the" in there). "See Spot gun" means "watch the thing whose name is 'Spot' (which we assume is the dog) performing the act of gunning (or shooting)". It's a really labored, and not funny, play on the well-known phrase "See Spot run" which means "watch the thing whose name is 'Spot' (which we know is a dog) running."