TV cops often hide behind car doors during gunfights. That’s about as effective as hiding behind a quarter pound of thinly-sliced Havarti. Out in the real world, YouTube is lousy with convenience store gunfighters who engage from behind racks of potato chips. Inspector — I mean Instructor Zero and Dirty Harry get it right: don’t forget you can fire through objects to stop a threat. (Quite why Zero would use a SMART car to make the point is anyone’s guess.) Remembering to know your target and what’s beyond it. And the fact that your adversary can do the same thing, too.