How will that help? She has to grab a gun first. If I was the perp, I would told her to stand still and make no movements without my permission or she gets it in her face. I would tell her to keep her hands up and only movement allowed is to get the money. Any other movement, she gets it in the face. Of course, you would need to overcome your deep rooted anathema of killing another human being.
I had a patient a vietnam veteran who was in the special forces with 200 confirmed kills he was suffering from PTSD. I got to know him and we talked about his time in service. I asked him was it hard to kill that many people?? He told me the hardest was his first kill it bothered him for weeks after that he said it was the same as killing a bug. As you may know you have to bring proof usually a enemy weapon ( but hard if they are civilians) if not witnessed for a confirmed kill. I am sure he had many more unconfirmed?? (he was not a sniper) specialized in seek and destroy missions. Last man alive from his unit. He told me was once
separated from his unit and lost in the jungle for weeks, he killed whatever he could find to eat and
killed anyone that he saw in the jungle (not american) to survive.
I recalled this to give an idea of what kind of killers are out there.