I will attack the ex-con angle as best as I can. These people sometimes dont understand why the world has rejected them. He realized he had done something wrong and tried to walk away. He was on drugs perhaps self medicating to a degree but we cant blame it on the drugs.
This is just sad. Yes, the police were eventually justified to use lethal force. But the police were also justified to not continue following him on foot.
Probably was having flashbacks -- arrests, childhood traumas, the god damn pen -- while he atoned on that walk. He got scared. When he was tased he was compelled to beat some ass which I feel as an observer he successfully carried out. I kind of feel based on the video he was actually compelled to beat some ass. The bad luck part for him was that the guy he beat up was a cop who had the ability to radio backup. Backup boys took his life.