Honestly, he expected it to be this difficult. He only wished it wasn't. Reacting solely with a deadpan stare at first, he continues filing the woman's nails, moving on to the next one slowly. He attempts to direct his gaze elsewhere-- at the nails, around the shop, at the ceiling, before Gon's continued staring gets on his nerves and he glares back suddenly.

Raising the hand with the nail file again, he points down at his work firmly, mouthing his words: I'm bu-sy!

As nice as getting away from here did sound... He'd have to come back eventually when he owed somewhere, and he'd rather not deal with the hag's punishment or her yelling.