Alright, so for a second, I was really disappointed. When the main part ended, I thought "Wow, wasn't really much of a punchline there." The joke was really just the ridiculousness of it, and the cop giving the other a piggyback ride accentuated that. As for the criminal teaching Matt how to drive, it was funny and well executed, but I'm almost certain I've seen that done in something else. So when this video ended, I was disappointed.
But then I saw the stinger, and it saved the entire skit. I cracked up. It was an extremely clever and hilarious ending, and I just pray that everyone who watches the video will stick around through the credits to watch it, because THAT was the real joke.