In a Krav Maga video, the instructor talks about the correct way to use a gun to threaten someone at close range – not to hold it in front of the other’s face, where there is a danger that one can get into a struggle over the gun, or even be disarmed, but to stand with the gun pointed at the other party, and the elbow pulled back, while pushing with the other hand to put distance between oneself and the other party. I suppose the same is true for a knife.
I think this is true of the power to harm in general. It is most effective when used defensively, and loses some of its strength if brandished overtly.
