Look, first of all, I'm a little tired of people in the broader, non-gun-owning world lumping criminally ignorant attempts at "self-defense" (dude in KC) and straight-up criminal assault (dude in NC) in the same basket.
However I also see lots of people who should know better acting like they've got some sort of special immunity because of a Stand Your Castle law in their state, or chanting "I WAS IN FEAR FOR MY LIFE" like it was a Get Out of Jail Free incantation.
The basic standard of "A reasonable* fear of immediate, otherwise unavoidable, death or grievous bodily harm to yourself or another innocent person" applies everywhere. In your car or in your yard, in your home, while you roam, or on a boat while afloat. Otherwise you may not shoot them, Sam I Am.
If you live in a state that passed a Constitutional Carry law, you no longer have to take a class to learn when you may or may not use your heater, but that just means the onus to get yourself educated is on your own shoulders now. Because, my dudes, they will still put you in prison if you screw up.
*What’s ‘reasonable’? That might be up to a jury.
.