When the ring levitated neatly up her side and into her pocket, he was still standing in the middle of the street. She couldn't see his expression at this distance, but presumably he was rather angry. She wrapped her hand around the ring in her pocket and found that her courage had failed her; she gave up standing still and ran into the bookstore. She could feel, suddenly, the ring pulling against her hand, trying to return to its owner. So Hermione grabbed the nearest book of Arithmancy, one-handed, and leaned against a wall and flipped through it, and tried desperately to look like an excited student and not a terrified thief.