Jim, Once you are in the mix it all happens very fast. You have to really decide what you can do morally and physically. It's easier for me to say what I said having had those feelings run up and down my back and stomach. You will not have time to think, Usually, that's why we train mentally and physically for this stuff. I hope you never see anything like that, but if you had, you would realize that there is really no decision to make. It's survival, and that is the strongest instinct we have. No matter how educated or peacfull one is, if you try to kill them, they will react with strength and determination that they never knew they possesed. Chances are you will know, if anything terrible "god forbid" befalls you.
Just have a plan, an alarm, a dog, a panick code that appears to shut your system off while sending out a "robbery in progress" call. and you weapon either on you or in the room, some just place a pistol in every room to avoid carrying, I am into cameras now. No one wants their picture taken. If you send the images to off premises servers, no one can grab the recording. I have seen guys walk up to homes, see the video cameras, and just walk away.They are a great deterent.
I must commend law enforcement on responding to holdup codes, my manager hit the old squeeze panick switches and they closed the street on both sides to traffic. I had LEO's come in both doors shotguns at the ready. Even here in Vero, my wife set it off on the slider, and they insisted on coming in and clearing the entire house. None of this "it was just a mistake", it was more like keep your hands where we can see them, until they saw for themselves that we really lived there.
Much can be prevented, but there is always the wacko who just doesn't care or is so stoned it dosen't matter, or a bump to the rear of your car, following you home if you drive a certain car, the list is endless. You may not want to shoot someone over a car, I don't, but there are people who will take the car and shoot you anyway. It's kind of hard to tell the difference, that's why I didn't understand the question, if you find you need to draw your wepon, then you are already in a pickle. If the guy advances on you, what's your plan, he has a gun, a knife a steel bat. Are you prepared to back up and put distance between you. You can't just decide to stop. He isn't going to stop if he's gone there. You said he wasn't stopping, tell me your choices if I misinterpreted something.