"Rockit" is probably not on anyone's list of Hancock's best compositions, but on the show he describes his composition of it in a way that explains a lot of jazz: "inside, outside."
Think of the first four notes of the tune: two close together, followed by two making a bigger jump. The first two notes are steps -- an A to a B; the second pair, however, is an augmented fifth -- an E to a C natural. When musicians are playing the notes normally found in the scale of the key a tune is in, they're playing "inside," but picking notes not found in the scale is playing "outside."
Those notes -- and it's often the fifth note of the scale raised (augmented) or lowered (flatted) that gives jazz it's sweet sound.
Hancock said he liked the way the two groups of notes sounded together, so he combined them with a "resolution" - a series of notes that ties them together and brings the tune back to the beginning.