"Joshua speaking: what the hell kind of absurdist insult is 'square'? He's clearly the same basic structure as any other human."

Graham chuckles again, and then shakes their head, smiling wider. "Graham speaking: No, Joshua, it's a way of calling someone a nerd or, or a dork. It's just a sort of insult. I didn't realize people used it, actually."

It's possible they're both stalling at this point; it's easier to sit and talk with Detective Sousa than face the possibility that he's telling them the truth: that they can't leave, that they'll find an ID card and other things waiting for them at the train station. It's also possible that they're just gearing themselves up to go back out into the cold without a jacket.