There's a moment, where Quatre thinks absently that was a little forward, wasn't it? and notes the observation for the future. He doesn't say anything about it, though.

"All right," he says, and steps back; his hand goes to Trowa's arm, again, but he drops it before touching him and just smiles. He turns and goes to get La Vie de la Souris from the proper bookshelf in the back.

(Everything in the library is sorted by topic and author; he's lucky it's not on another floor entirely.

If it was, he'd be reading another book.)