Am I right to say that your argument can be summarized as, "She didn't deserve it, but her actions were deserving of it"? Or maybe "merited"?
I'm genuinely confused by what you mean by "deserves".
(just to be explicit, the disagreement we have here is very much about what the word "deserves" means rather than anything productive)
Another quick aside since I suspect this is a second point of confusion, "lethal force" does not mean "with the intent to kill", it means "force that is likely to cause severe injury or death".
It.. is not. I suspect that you have some fundamental misunderstandings of firearm safety and I would not feel safe at a range with someone who thinks this way.
Wikipedia: https://en.wikipedia.org/wiki/Deadly_force
> Deadly force, also known as lethal force, is the use of force that is likely to cause serious bodily injury or death to another person.
Cornell Law School: https://www.law.cornell.edu/cfr/text/10/1047.7
> (a) Deadly force means that force which a reasonable person would consider likely to cause death or serious bodily harm.