It reminds me of the Atlanta Wendy’s video. The cops talked and talked and talked trying to reason with the guy and then the guy fights them and took a shot at one of the cops with the taser.
Law enforcement departments have probably already looked into this, but some sort of instant, non-lethal, immobilizing foam that instantly hardens on the suspect, would be very effective in keeping him from squirming around and reaching into his waistband for something. Better than a tazer.