First off Police men are "civilians" as well. Policemen aren't in the Military so they are civilians. I hate it when folks call a average guy a "civilian" and then try to elevate the police to a higher plain...just a burr under my blanket.
Second Buckshot, no matter what type or wad would not be effective at the ranges stateed, it has no power left and might break the skin and cause a nasty infection, but that is about it, and who in their right mind would launch 9 projectiles into a trailer park setting? you are responsible for each and every pellet that does or doesn't hit the bad guy, but does hit little 3 year old Cindy playing in the kiddie pool out fronm of their place.
Third if you have a modicum of skill and a pistol or revolver of reasonable power and velocity it isn't that hard of a shot. Most B class USPSA a shooters can hit a C zone sized target at 100 yards with some regularity with a slow .40 cal so it can be done....BUT you have to be fairly "frosty" to do it under stress. Good Job! and good shooting! I bet he saw his front sight and has shot that particular pistol a few times.