The Problem
Tactical training in the proper use of tools such as your sidearm, TASER, and baton is required in law enforcement. This is important, because when the time comes to use these devices in a life-or-death situation, their successful deployment and use needs to be smooth, accurate, and automatic. If you have to think about things like proper hand placement, or sight picture, or other fine details then your mind is too occupied to keep a proper focus on the developing tactical situation and optional strategies that can provide the best possible outcome.
Similarly, when it comes to using your voice in a critical situation you need to have built skills through practice ahead of time and planted memories of alternate approaches to common scenarios in your mind so that you can draw upon them to de-escalate encounters.
Too often during confrontations law enforcement officers simply repeat ineffective commands. "Show me your hands! Show me your hands! Show me your hands! Show me your hands!" If it didn't work the first four times, it is not likely to work on the fifth. So what can you do?
Many officers will simply repeat "Show me your hands!" and add "Do it now!" for emphasis, and hope for the best. And if that doesn't work they know they have to go hands-on and force the subject to comply. But that puts that officer, the subject, and fellow officers at risk.