In chapter 9, Sydelle Pulaski puts a notice in the elevator about her lost shorthand notebook. It doesn't result in the return of the notebook, but residents immediately follow up with notices of their own and post them inside the elevator on all four walls. Among the notices that report lost items, advertise services, and invite residents to meetings and parties is a notice that is meant solely to tease Turtle. It says that six clues were found and presents them as: "BRAIDED KICKING TORTOISE 'SI A BRAT."
Upon reading that note, Turtle had rushed into the coffee shop, screamed, "The braided tortoise strikes again," and kicked Theo in the shin. Theo was surprised. Chances are he hadn't seen the note in the elevator yet and had no idea what Turtle was carrying on about. Dough Hoo, not Theo, had made and posted the sign, but Turtle had evidently presumed Theo was its author. Theo was surprised because he got kicked for something he didn't do and probably didn't even know about, and he was surprised by Turtle's war cry, which wouldn't have made any sense to him.