When they return, Rosita throws herself on him joyfully, and the man chuckles oddly: "Now then, Rosita. A little decorum." He's still in the grip of it, he still thinks he's a God. He doesn't know yet what he's allowed to have. "He's always doing this, leaving me behind!" she shouts at the Doctor, looking for sympathy. The thing these words do to him is less about sympathy, or more than.
By the hand we're lead toward the Next TARDIS, which the Doctor can't wait to see. Through the house, into the home and the garage. "You were right though, Rosita. The Reverend Fairchild's death was the work of the Cybermen!" Of course she was. All through the house there's luggage, baggage the Next Doctor carries with him if you will: "Evidence. Property of Jackson Lake, the first man to be murdered." The Doctor nods, understanding part of it at last. His new friend changes the subject excitedly, moving smoothly away from the terrifying feeling that man's name produces: Jackson Lake, the first victim. "Oh, but my new friend is a fighter, Rosita! Much like myself! He faced the Cybermen with a cutlass! I'm not ashamed to say, he was braver than I! He was quite brilliant!"
The Doctor and Rosita, Companions to the man, share a conspiratorial look as he sonics Jackson Lake's luggage open -- "Are you whistling again?" -- because they know, both of them, what it is to love him, and the burden only Companions know. All the little things. "That's another man's property," Rosita calls out while the Doctor takes down a particularly important valise. The man sits nearby, once again jolted out of time and space by a horror and a sadness, staring into nothingness. The Doctor asks how they met; how she came to be his Companion.
"He saved my life. Late one night, by the Osterman's Wharf, this... Creature came out of the shadows. A man made of metal. I thought I was gonna die. And then, there he was. The Doctor." The Doctor looks from Rosita to his friend, smiling at them both. This little world, made of pieces. "Can you help him, sir? He has such terrible dreams. Wakes at night in such a state of terror..." He stands again, having come back to them. No more dipping in time for now. "Come now, Rosita," he says, softly approaching. "With all the things a Timelord has seen, everything he's lost, he must surely have bad dreams."
To be understood, to be loved like that: It's not just about making the Doctor a Companion and a strange man the Next Doctor, it's not just about feeling what they felt. This is a man who has walked the halls of the Doctor, thinking them his own, and travelled through the doors, open and shut. He looks at Jackson like he looked at Donna, or the Master, but the deeper truth is that this sadness is real, either way. Jackson Lake has a biography, but that doesn't mean this pain isn't for the Doctor as well. Rosita worries, and the Doctor worries with her. "Oh, now, look. Jackson Lake had an infostamp... Doctor," John Smith says, "The answer to all this is in your TARDIS. Can I see it?"