The best man at my wedding is a Sgt with East Moline IL. In the video below the plain clothes officer that comes up is with his agency.
The suspect was wanted for an assault at the local soup kitchen. For some reason he punched a volunteer in the face and fled.
What happened out of camera range was the suspect mounted the officer and was punching him in the face and slamming his head against the concrete. He then bit a chunk out of the officers eye brow. The officer was able to deploy his weapon and fire two contact shots into the suspect killing him. Even though the plain clothes detective was yelling verbal commands and striking the suspect from behind the officer on the bottom did not hear him and could not see him because blood in his eyes. This shooting is a good as it gets and has already been cleared.
Keep this in mind when you contemplate on under what circumstances you would use deadly force. I don't think they cover this one in IDPA. BTW we just trained for his exact event this weekend before I knew about it.
Police video: Centennial Bridge shooting