There is a place he does not go.
Inside the infinite universe tucked neatly in a police telephone box from 1960, there is a room in which the Doctor does not dare tread. It is not that he can't find it, because every time he changes the desktop and gets lost, he stumbles upon it. If he goes for a swim, he finds it. If he heads for the library, he finds it. The TARDIS does not appreciate his attempts at evasion and forces this unwanted room upon him with such force that he wouldn't be surprised one day if he walked into the control room and found the other room instead. His old girl was nothing if not stubborn.
But this was a day he did not need stubbornness.
Manhattan is still raw in his hearts. River is deposited back into her flat, which is a painful reminder how very close to the Library she is. He never thought he would ache to wish her well from the threshold of the Stormcage.
Currently, he's parked in Victorian London. A nice cloud keeps the questions at bay, although it is only a matter of time before Vastra and Jenny will be hammering on his door and asking questions he is not capable of answering.
The Doctor isn't paying attention as he strides through the new halls of the TARDIS. He misses the warmth of the old console, but all he can see is Amy lounging against the controls and Rory toying with things he shouldn't and Brian sitting for three days to watch a cube on the Doctor's orders. He always had a sneaking suspicion that the TARDIS, upon remodeling itself after the crash in the garden, altered the desktop to match the particular shade of Amy's hair and the fire which fueled her need for adventure. The fire that would lead her to Manhattan, to the angels, to the edge of a roof looking over 1938.
That fire would give her the courage to leap.
When he had returned from escorting River safely home, upon turning the key, he stepped into a world of blue circuitry. The Doctor had not changed the background to this, but also didn't have the hearts to change it back as it had been. And so he let the TARDIS mourn in her own way.
These were the thoughts that crowded in the Timelord's mind as he took three sharp turns past the swimming pool. His hands fiddle with a small key that he has slipped from his pocket. This is always one of the worst parts. Just as he did for all the others, it is time to lock up the Ponds' room.
The TARDIS is both kind and cruel enough to line them up at this point in time.
He passes Rose's first. It's a relatively blank door, save for the scribbles in her loopy hand that read "Property of Rose Tyler – KNOCK Before Entering, Doctor!" He can still see her, a young traveler full of fresh wonder, adding her personal mark on the TARDIS with his hand helping her steady the laser engraver. The next part had been added hastily with a tube of lipstick, drawn on shortly before her encounter with Torchwood. "My room, my rules," she had said with an eye-crinkling smile before closing the door behind her.
Next is Martha's. She had glued a plaque of hers onto her door that read MARTHA JONES, M.D. in small capital letters. "I want this back," she had intoned seriously as he handed her the glue bottle. "It was a birthday present from my mum and I intend it to sit on my desk someday." She never did ask for its return.
Sitting third in line is Donna's bedroom door. It's the only one with built-in lettering, as if the door had been built specifically for her. Of course, it had been. After several weeks of trying to graffiti her name onto her door, Donna had found that the TARDIS refused all attempts of the sassy redhead to claim her property. The Doctor had followed a source of commotion to find her having a shouting match with a silent and inanimate door. "Listen here, box, I don't care how special you are, you're giving me a door whether you want to or not! I'm a long term passenger, so you might as well deal with it!" The next day, in golden letters, the title DONNA NOBLE appeared on the door – along with the phrase Sassy Earth Girl added underneath.
At this point, the Doctor believes that he has reached the Ponds' door. He is too caught up to notice that it is missing the traditional markings. That the word Ponds is not scribbled in Amy's warped writing and Rory's additional message – KNOCK DOCTOR – is absent. Instead he reaches for the handle and pulls open the door and does not think to wonder why it is unlocked until it is too late.
The TARDIS is tricky and oh, so clever.
The Doctor makes a frantic scramble for the door, clawing desperately at the white smooth wall that the door has disappeared into. Finding nothing, he turns slowly, sinking down against the wall onto the floor of the room he never enters.
The blank white walls enclose a long pathway that disappears into the darkness. He does not want to accept that the only way out is forward. With the weariness of an old man, the Doctor shows each of the thousand years he has lived as he struggles to rise. With the deliberateness of one enduring torture, the Timelord takes his first step.
The white walls spring alive. Where once there was only a blank panel, a video screen turns on. After a short moment of static, the Doctor's personal hell begins...
With a laugh.