As he drove his newly acquired vehicle from the scene of the crime, the carjacker noticed something strange -- the entire back of the van was stuffed to the brim with explosives and accelerant, a rat's nest of gas cans, wires and switches. This is the point at which your average person would jump out of the car like Charlie Sheen in Navy Seals without a second thought. The most civic-minded of us might call the police, once we were well out of the blast radius.
For most of us, the 911 call would go something like: "Holy balls! Holy balls! Holy fuck fuck BALLS!"
But this unnamed auto thief couldn't bring himself to flee the vehicle -- he was in the middle of a neighborhood, surrounded by buildings filled with hundreds (or maybe thousands) of innocent people. Instead he drove the bomb-rigged van some 15 blocks until he found a deserted stretch of waterfront where he could park it. Then he called a police officer he knew from past run-ins with the law and told him about the bomb.
Because the first thing cops do after arresting you is exchange phone numbers.