"You know when grown-ups tell you everything's going to be fine and you think they're probably lying to make you feel better? 'Everything's going to be fine.'" So he clears the wall and Amelia gapes at him, and he's so excited about whatever happens next that he's breathing super hard. He is excellent when getting into trouble. So he sonics the crack and it opens wide, and tries to talk to the voice, but a giant eyeball appears and stares at them through the crack, and then shoots a laser at the Doctor's nuts.
The crack closes, and the psychic paper explains, once again, that Prisoner Zero has escaped. Meaning that Zero is in the house. So the Doctor runs around the house for awhile with ADD, and then -- this part is filmed in such a way that it makes no sense at this time -- realizes that there's an extra door in the house that leads to an extra room in the house, that you can't see except for the corner of your eye. (So now we've got three things that could/should just be their own episode. There will be many, many more.) Before the Doctor can explain the explanation above, the Cloister Bell starts ringing, and he screams and runs outside to check on the TARDIS.
She's not doing so well. Science things are happening to her, as a result of the sudden explosions at the end of the New Years episode, and she's recreating herself inside to accommodate the budget cuts, and so he's got to get in there and stabilize her with a "five-minute hop into the future." Sort of, I guess, like driving about once you've gotten a jump from a helpful stranger. Amelia's stuck on how it's a time machine, which is awesome, but she immediately hands us the next part of the episode: He says he's only going to be gone five minutes, but this is patently -- and, in her case -- empirically untrue. People leave, and they don't come back. He swears he'll be back immediately -- "I'm not people, do I even look like people?" -- but Amelia knows people better than this newborn: They come into your life for a moment, give you a little kiss, and then go away again.