Personally, I dont think this should go to court. I dont think the officer harbored ill intent. I think he was afraid, and was likely afraid from the get go, and made a fear based reaction.
I think we need to ask ourselves, why was he afraid? Chasing a gun carrying criminal a 2 am? I'd call that pretty scary, no doubt about it. I wouldn't want to do it. But then, I race cars. I battle fear for the entire lap, every lap. Anyone who has ever wiped out, rolled, or slid off track, swapped ends, etc, knows that fear. But we still do it. And we maintain control of ourselves throughout that fear.
Officers know what they are signing up for. You gonna be a cop in Chicago? Thats means at some point, your gonna see and do some scary stuff.
End of the day, this officer caught a criminal, and the criminal was in the act of complying with his orders. And out of fear of what COULD happen, he shot the criminal and killed him. He was afraid, and so ended the possibilities, the "what coulds". Criminal? I dont think so. But like the race car driver who can't handle throttling into the apex instead of breaking, this guy maybe shouldn't be a cop. And like that fearful race driver, when he wipes out as a result of him breaking out of fear, taking others with him, the body that sanctioned him owes those other drivers. They issued his license, said he was good to go. So too, does Chicago owe a debt.