Frankie has to go back to the library to get the twine that runs the length of the tunnels—since none of the Bassets thought to do it.
She feels lonely while she does it, because it makes her realize that she's still left of out Matthew's world, after all.
But as she's tracing the path of twine, it goes slack and she realizes that someone did think to go get it.
When she tries to hide, she burns her arm on a steam pipe. And when she finally emerges, she runs into a guard who tells her that they're investigating the tunnels for the perpetrator of the pranks, but that she shouldn't worry her pretty little head about it.
Frankie gets back to the dorm and hops into the shower in her clothes to cool of her burn, which is seriously painful.
When she gets back into the room, she tells Trish that she fell into the pond, but Trish knows that she's lying.
She still won't give up her secrets though, even when Trish presses and gets upset.
Finally, Trish just gives up and goes to get her some ice. We like to imagine she rolls her eyes, too.