Fear and Loathing in Las Vegas Lesson Plan

Why does Duke hypothesize what would happen if an officer caught him shooting the Magnum .357 in the desert?

Duke often lets his mind, and therefore the narrative, run through hypotheticals of what might happen if he were to be caught by an authority figure. He conjures up the worst case scenario (in this case that he is locked in a jail and beaten), which inevitably never happens; somehow, Duke always manages to get away with his various shenanigans. Which begs the question of why he runs through the possibility of getting caught each time. His hypotheticals are always hyper-dramatic and contain detailed dialogue, down to witty retorts on Duke's part. It is as if...