"It's considered a little impolite, since you'd get water everywhere."

Jae's not sure what kind of mentor he'd be concerning adjustment to modern life - he's a little skittish about the city still, too. (And he's not sure why this guy is so fixated on water.) "Sure. It's better during the day, too."

The beach isn't abandoned at night - he's been down there for fireside bars - but swimming in the dark? Not a good idea.