The Next Doctor starts to rebel: Jackson Lake is dead. That's how he wants it: "The Cybermen murdered him!" But no body was found, and he kept all the suitcases but couldn't open them. He takes the fob watch again and flips it over: on the back is a monogram: JL. Jackson Lake. The secret was in the watch, but not like they thought. Because think about this, first of all that Doctor-Donna was right -- you fix a Chameleon Circuit by linking fragments, by superseding the binary -- but second of all it's the strangest coincidence of memories and sad stories happening here. Tim Latimer and John Smith, long ago in an English winter, both took part in Jackson's general story here, in opposite and troubling ways: it was Tim who carried the watch, and Smith who was had to leave, in the end. He thought he was a lie, just like Jackson Lake now does. And then you have the more obvious parallels with Donna, in which he has false memories to match her missing ones, and they meet in the middle, at their own potential, their strength and wisdom. In the way they dream of leaving, but never do.
"You became the Doctor because the infostamp you picked up was a book about one particular man." The Doctor projects the Doctors, one by one, all nine, on the wall of their home. Their beautiful memories, their faces. "The Cybermen's database, stolen from the Daleks inside The Void... everything you could want to know about the Doctor." It stops on Ten's face and Jackson jerks upright, recognizing the face of his friend. "The infostamp must have backfired, streamed all that information about me right inside your head."