Just because he doesn't technically work here doesn't mean he doesn't know the place like the back of his hand. Erik loves books, and what else is a semi-retired man supposed to do with his time, outside of his music?
So when he sees this poor lost soul searching helplessly in the New Releases section, he can't help but offer a metaphorical hand.
"Not finding what you want?" he smiles, peeking over her shoulder to see what she's looking at.