You could just answer the door. Sorry to be snarky to you specifically, but this comment section is weirding me out. Maybe I live a sheltered Canadian life but

You could just answer the door. Sorry to be snarky to you specifically, but this comment section is weirding me out. Maybe I live a sheltered Canadian life but this seems like information overkill. When somebody knocks on your door you should just answer it and not live in a bubble. If you find yourself on the other side of a door with a knock and walk away to find your phone first... I'm worried you have retreated from the normal world into a sheltered modern depression.