There is a part of yourself you have to close off to watch scenes of people being hurt. Sympathy is a natural sentiment. It is built into us, and it never goes away, but we can teach ourselves to ignore it. But why do that?
Here is the thing: you do not really make yourself harder by watching movies. You make yourself emotionally stupider, more isolated, and more paranoid. And being paranoid might occasionally mean that you notice something other people don’t, but the difference between paranoia and alertness is the difference between continual arousal–which I can say from personal experience is exhausting–and appropriate situational arousal, and it can be argued that continual arousal actually blunts your intuition and survival instincts. Most of the best soldiers I have known are very relaxed most of the time. You can go farther that way. Much farther.
This is all good. I don’t need violence in my life. And I am usually always Condition Yellow anyway. But in all my life, there have only been a handful of times where I was in actual physical danger, and I was able to get through those without actual violence. And I may go get my CCP as a bookend. It’s rare, but I do occasionally go places where it might help to be able to legally bring a friend. One the one hand I stop adding unreal fantasies to my unconscious, and on the other I prepare for the unlikely event of actual violence. This makes sense to me.