It took him several moments to realize it, but the Doctor finally looked at his surroundings and came to the conclusion that he was dreaming.
He was surrounded on all sides by Daleks that were impossibly large and impossibly there.
It was an odd thing, to realize that one was dreaming. Lucid dreams had never been his forte and he seemed to not be in control of this dream either. A vague thought of a yellow, bird-like creature crossed his mind, then disappeared as he was sucked into a jumble of words and images.
Davros had returned. He tried to move his mouth, to say something, but he could not make a sound. It was odd for him not to make noise; he was the Doctor. He was always talking, always explaining, always monologuing. He did so enjoy the monologuing.
Davros cursed his name as Daleks spun around him out of control. There stood another him – a perfect copy – and Rose and Sarah Jane, and everyone else this face knew and held dear. And brightest of all, shown Donna. He could tell there was something different about her, about the way she walked and spoke. They flew away in the TARDIS and everyone left, everyone except her.
And then she was rattling on about Felspoon and he watched his other self, the pit of his stomach filling with dread. He couldn't bear to watch this happen to her. He knew what was coming. He closed his eyes.
And just like that, he stood among flakes of snow on planet Earth. He looked around frantically for any signs of Donna or the others, but saw neither. Instead he saw himself, prancing around like King of the world. There was something different about himself too. He could see it in his own face.
He heard himself speak and realized what exactly he had done. How was this possible? How could he lose himself so completely? Where was Donna?
Captain Adelaide Brooke, for he knew her identity simply from her face, drew her gun and he saw it. He saw it. He felt his feet cemented to the snow as he tried to run. His other self walked smugly back to the TARDIS, then heard the gunshot.
The horror of what he had done, the shame, the guilt, overwhelmed him. He fell to the snow, as did his other self, but only the dreaming Doctor cried.