Don't worry. A woman you met on [throws a die] a construction project is going to explain quantum mechanics to you in real life

I said that as a joke but since she does handle a lot of manual work like that, maybe they could've met while Ristretto was getting some work done on a room? In any place she designates as public she's pretty friendly and enthusiastic about starting conversations, so they could've hung out over whatever period of time it takes to expand a room and convert it into a recording studio or something like that.