In a home you can nearly always throw out the 21ft rule. Most of the small "economic" houses I am in when i work I try and get out of and do my business outside. With that being said, here in FL if you feel like you are at risk, you can drop that dude without any commands. We had one a few weeks ago. Teen starts slamming on this guys door at 4am. The homeowner thinks something might be wrong so he opens the door. The teen charges him so he fires and kills the teen. The guy never even had to go to our station for an interview.