Glen and I are actually in 100% agreement on this.
"Anything you say can be held against you in court."
Anything you say, other than the direct command, is distracting from what you want the guy to do. Any excess verbiage takes time you may not have to get his attention.
Angry? There's no need to get angry. You need to be cold and calm to perform as needed to save your life.
"I shot the man to save my life."
sounds a lot better than
"The scumbag came at me, so I popped a cap in his butt just to teach the MF a lesson."