What should he do? He'd been keeping an eye on Tomoko while she made her purchase (even when her ribbon had been all he'd been able to see), and had seen her take another way back. Since he was prepared to listen for her footsteps, he could guess where she was from the sound. And from the pauses between steps, it sounded like she was tiptoeing.

Maybe he was wrong? Probably it would be condescending to fake surprise, though. "Ah— Tomoko-chan." He turned around. "Are you ready?"