Once one leaves their home (or business, place of sojourn, etc) to pursue someone, doesn't that change everything? I don't know the exact wording of the law, but I recall Dr. Max Cooper mentioning something about you have to make attempt to avoid the conflict, with the exception being you aren't expected to leave your home. I believe the example Dr. Max Cooper uses is if you have an "encounter" on the freeway, the other driver flips you the bird, you return the favor. He pursues you and you drive home, get your firearm and he comes on your property and you shoot him that in that case, use of deadly for is not justified. The alternative to avoid would be to drive to a police station, public place and call for help, etc.
I am NOT saying that I agree with it. The law is what it is. I hope I'm not misquoting Dr. Max Cooper, but that's what I recall. That once you pursue, you then become the aggressor.
Anyway, that's some sketchy shat for sure.