Don't you imagine it is easier to keep a level head in a confrontation when you are confident of your ability to defend your person, should it become necessary to do so?
No, because this requires clairvoyance I don't possess in order to know the other guy doesn't also have a gun.
I mean, I'd also be pretty level-headed if I knew I could explode people's heads instantly with my mind, but we don't live in that sort of universe.