About 30 years ago a friend that I worked with went to another police department. They carried 1911's, we carried .38 revolvers. He got a call of a disturbance in a bar and went in as soon as he got there, not waiting for his backup. Yes, I know and now, so does he.
As soon as he cleared the door a drunk him in the back of the head with a bottle, knocking him unconscious. He regained consciousness with the drunk sitting on his chest, trying with both hands to pull the trigger of my friend's gun with it pointed at him, a few inches from his face. He was squeezing the trigger so hard that his hands were shaking with the effort.
As soon as he came to enough he smacked the guy on the side of his head and took him into custody. If he'd have made the same mistake (entering the bar alone) before he'd switched departments, he'd be dead now.
Ever since then I've thought that the police should carry a gun that has a manual safety. Many police officers who are shot are shot with there own guns. Sure there are some who will know how to release it, but if it just gives the officer a one second delay . . .