[He just elbows her a little in response to that joke, but even that can't deter him from the subject at hand.]

I'd rather go back into the portal between you and me. [Dryly. So dryly, but he takes a deep breath and looks down in the schoolyard again.] If we head down there, just remember we've gotta stay on guard. This place is pretty unpredictable sometimes. [He turns his head.] There should be the roof access door somewhere up here, right?