He opens his mouth to retort, but the point Gon makes is unavoidable. Closing it again with a quiet click of his tongue, he leans over to toss the broken nail file away, grabbing a new one.

"Fine, fine! Just sit down. I'll get to you in a second."

He was almost done with this woman, anyway. And so, hoping that Gon will listen to at least that much, he returns his attention to her nails, finishing up and assuring that they're done just as she asked before amping up the innocent politeness to his tone and pretending he hadn't just bossed Gon into a chair.

"Alright, all done! ...We thank you for your purchase and hope you have a killer day!" His nervous, shaky and forced smile is almost painful as the lady gives him a suspicious look and Gon a kind wave with her newly fixed-up nails before she heads out. Almost immediately, Killua sighs and lets his shoulders sink.

That could have gone a lot worse. He guesses his boss was in the back listening to her music, again...

Turning on his heels, he shoves one hand into his pocket, the other waving the nail file at Gon. "Oi, why do I have to do your feet? Pick something easier!"