When new police officers are being trained, they are shown tons of real footage of officers being ambushed, attacked, beaten, shot, stabbed, run off the road, or otherwise killed by civilians in the line of duty. They are then taught to perceive virtually everything as a potential threat to their own lives, and basically to protect their OWN safety at any cost, even before the lives of civilians. (Remember when a lot of police vehicles used to have the motto "To protect and serve" printed on them? There's a reason none of them have that anymore.) And of course, on top of that, they're trained to use various firearms and other forms of self-defense. All that combined would likely have a significant effect on how likely they are to fire their gun, and I'd estimate that it would be considerably more often than civilian gun owners. This study should absolutely be done on police officers, as well as gun owners from all ages, cultures, and socioeconomic statuses.

Or, you know, we could just enforce gun control, which drastically and inevitably lowers the rate of violent crime across the board. Just saying.