Oh?! [ and then, after a moment, when it's clear that he's not in trouble: ] Oh! That's... I'm probably not very interesting to watch, but I'm glad I was entertaining you, at least?

[ his eyes glance back down to the arm, and after a moment's hesitation he continues his work - his gaze darting up and down, just enough focus on the man to be polite and just enough focus on the arm to guarantee he's not misplacing anything. ]

Do you... like taking things apart? [ it's a polite question, if a novicely worded one. the boy isn't very used to keeping a conversation going, evidently. ]