wideym, could you meet up with her again and ask her to go to the range with you?
After training her with a totally empty gun (check 3-4 times, and teach her to check 3-4 times) and teaching her the four basic gun-safety rules... then show her how to shoot it with real bullets afterward.
Maybe something will spark inside of her after she has actually shot the gun, she'll be more comfortable with doing it in a real life and death situation.
Sure, I can be wrong, and she can still give up after this, but we've got to try somehow, and everyone is different to an extent.
You've got to wake her up, because she's literally in some kind of dream world of some sort; someone has brainwashed her into thinking this way.
You'd have to wonder about some of these peaceniks out there; if you ask them "Would you kill death, if death were killable?"
Would they say they don't want to kill, and let death still reign over themselves and everyone else?
That'd be crazy, right?
Well, it's similar to letting a brutal rapist / murderer live, as well! As harsh as it might sound, you've got to let them know: If you willingly sit there and do nothing, while letting a rapist / murderer have their way when you had the power to stop them, then you're only helping him/her inflict that same pain upon others in the future. You've got to suck it up and take these bastards out; not only will you do a rightful service to yourself, but to the whole people! Now that you've killed a murderer or rapist... you've now saved countless number of lives from torment and misery!
Look at killing a criminal the same way you kill a cancer.
Tell her this!