He goes out on meaningless/powerless "neighborhood watch" packing heat, gets fixated on some kid who is staying there who was doing nothing, he was apparently projecting his anger over past break ins at him based on his phone call, and then gets out of the car at some point to pursue him with his gun. THere are others possible, some which may well have occurred, soem that did not... but we will never know for sure. But that right there is several negatives that happened.