Heads: If you train well, practice, learn to function under stress, you will have a much better chance of surviving any lethal force encounter. This is no exception.
Tails: If you train well, practice, learn to funtion under stress, the DA, if he's a jerk (and what DA isn't) will try to paint this activity as "extreme, gun-nut, desire to fight, practicing at killing".
I would say that the courts are one thing, and real life is another. You have to survive each in its own way. To do that, you need to apply appropriate "weapons & tactics" to each. In the latter, this scenario, leaving a potential lethal opponent behind you isn't really smart. If you attempt to kick the weapon away, you must spend a significant amount of real (gunfight) time co-ordinating such an action, and make sure that you kicked the weapon far enough away so that the BG can't readily get to it. THAT takes your attention away from the rest of the fight, and that can be lethal - from one of the other guys. How well you might be able to "pick up gross movement" - from behind you, especially with bullets flying at you, - is open to lots of serious question.
In the former situation, it means being very careful about what you say when, and finding a really quality lawyer.