"Hmm? No reason particular."

There's no real indication of a subject change or repressed topic, any desire to avoid expressing a conscious thought.

Mal swivels back and leans forward over the control panels accessible to the pilot's chair, reaching up to three switches which get flipped in an incomprehensible order.

The resulting effect is music: rigged to be sure from some set of speakers Mal probably won in a bet. They sound awful. Mal is smirking.