[Killua pauses, then leans with a scowling sulk over the handle of his pushbroom, crossing his ankles with an unpleasant squeak of vinyl.]

I'm the last person who wants to contact my family about anything. People's imaginations really run wild...

[Killua huffs, then gets back to scrubbing, his brows knit crossly, creasing his forehead.]

I think it's more like teachers are afraid of my parents finding out I'm in trouble, cuz they think they'll get in trouble! I'm usually the one who's punished, though; people never think of that...

[All the emphasis in his words are when Killua's scrubbing particularly hard. But still, clearly notes of frustration. Yep, definitely working out some aggression.]