If you look closely, the perp attempted to run the officer over with his imaginary car.
And the police imagined they feared for their lives.
Don't quit your day job, your comedy is weak.
The officers entered the cell with the intention of searching the offender, who was seated. The Officer without a hat tried to grab the offenders apparently arm to stand him up for the search, and the offender kept pulling away from this officer. After some conversation the offender stood up and was searched and apparently something was found. The officer with the knit cap rubbed the offender on the top of his head, a bit insulting, but harmless nonetheless. It appears the offender took exception to this disrespectful act and as the officer turned away, the offender moved towards the officer and tensed up, definitely an assault, the officer turned around and they both grabbed each other and wrestled around in the cell the officer with the knit hat then used his closed hand to strike the offender to get him under control.