What makes a killer?

A police officer in England is alive today, simply because her attacker chose not to kill her. In the video below, a man in handcuffs attacks the Sergeant, knocks her to the ground and pounds her head into the ground, knocking her unconscious. Watch the video:



If you listen carefully, the officer's breathing changes as she goes unconscious, and remains that way for almost a full minute. During that minute, the man could have simply strangled her to death, if he had wanted to do so.
One commenter said:

Damn good job the officer didn't have a gun or a tazer as it could have been much worse!

Which is ridiculous. The only reason that the officer is alive is because the man who attacked her wasn't a killer. He had the means and the opportunity, but not the will. having a weapon doesn't make a person into a killer, having the mindset of a killer does.

As for me, I am not willing to bet my life that a person who attacks  me is not a killer, so I carry a gun, and hope like hell that I never have to use it.