This idea came to me when I was rewatching Bad Wolf and The Parting of the Ways (for the millionth time) and I noticed that the Doctor made a comment about how the Delta wave would take three days for him to complete perfectly with the special settings to keep it away from the Earth. He had twenty two minutes. So, what if he had a Doctor's help? But then again, three days. What if three Doctors worked on it? So, this happened.
Disclaimer: I do not own Doctor Who, nor do I own Christopher Eccleston, as much as I may wish to own both. The lines in here that sound familiar are direct quotations from the show itself, as even though this is bound to go terribly AU by nature, I wanted to follow as closely to RTD's storyline as possible.
The Doctor glanced over at Rose, who was perched on the side of what had been the Game Station Office, and he handed her another tube he had pried out of the system. Already in his head he was running over the options, how close he was to losing her, losing all of this.
He could hardly think through the powerful loathing of the Daleks sitting forefront in his mind. The False God of the Daleks was alive and had brought back his worst nightmare, and somehow he had missed a Dalek in the Time War. He couldn't even be surprised, just so unbelievably tired with the universe. It was far too much for him to hope that he had wiped out all of the Daleks along with all of his race. He had hoped, back then, to wipe himself out too, so it was only fitting that two beings he wanted gone has survived. The universe was funny, there, always in balance, always in numbers that corresponded. Daleks and Time Lords, gone except for one of each. It left a shard of ice wrapped around his hearts, but that lifted the moment he focused back in on Rose. Rose, his golden haired companion, who was sat looking expectantly at him, as they all looked expectantly at him.
Sighing, he told them what he had figured out. "Trouble is, wave this size, building this big, brain as clever as mine, should take about, ooh, three days? How long 'till the fleet arrive?"
One of the workers answered him, telling him they had twenty two minutes until Dalek impact. Fantastic. He racked his giant, genius brain for ways to get them out of here, ways to get them off of this platform. The only things he could think of involved leaving these people to die and taking himself and Jack and Rose to safety somewhere far, far away. That thought was so tempting, but he also knew even as he thought that that the temptation would never pull him in.
He kept working, and as Jack told the fighters what the plan was, he called Rose over to him. He ignored Jack's plan, knowing already what he was going to say, and instead turned toward his other companion as she said, "Suppose-"
She cut herself off, and he waited, then asked her what she was going to say. He knew where she was going to go with this, was going to ask him to override his own timeline, and he couldn't do that. He told her as much, and then it hit him. He was a genius, him, and he could keep her safe. He had promised himself, had promised Jackie Tyler, that he would do everything in his power to keep her safe. As much as the Doctor needed Rose Tyler by his side while he was alive, he couldn't let her die by his side. So, he did what he had to.
Pasting on that wide grin that made her answer with her own, the Doctor said "Rose Tyler, you're a genius! We can do it! If we use the TARDIS to cross my own timeline...yes!"
He led her into the TARDIS, not stopping to let his mask fall now. He would feel and show his sorrow later, before his eventual demise, but she would not see that. He told her to hold down the button, and made some excuse of what exactly it did, and she did as bid, listening, trusting him as always.
It hurt, so badly, seeing her expectant face waiting for his command and his return as he stepped out of his magnificent ship for what he knew with unquestionable certainty was the last time. He stood outside for a moment when the doors were shut, grin falling, eyes pooling with hurt, and he looked on, helpless and knowing he could not say goodbye, because goodbyes hurt too badly without the words actually being said. And he knew Rose wouldn't go if she knew what he was doing. Oh, Rose.
He pointed the sonic screwdriver at the TARDIS, setting off the sequence to send Rose Tyler back to the Powell Estates, back to Earth, back to the waiting arms of Jackie Tyler and Mickey Smith. He supposed his Emergency Programme One was a goodbye, in a sort of way, anyhow. It was fitting in a way that he wouldn't be the one to say the words explaining what to do; it would be a projection of him, a ghost. He would be a ghost himself, soon enough. That was alright, too, so long as he stopped the Daleks and his Rose was safe.
The Doctor turned back to the task at hand, this nearly impossible task that would end in so much death, with so much more blood on his already sopping crimson hands. What was one more planet gone? a terrible voice in the back of his head asked him. Too many gone, he answered himself, and he knew then that he was teetering on the edge of being able to do this. Then he thought of Jack and his assembled fighters below him, and thought of the people he knew that would fight until the end, the people who would choose dying human and heroes any day over becoming a monster and living on. The Doctor just wished he had had that choice himself. Sighing, he resigned himself to creating the Delta wave, wishing for help and wishing for time. A Time Lord, and it seemed he was close to running out.
Okay, so I am thinking maybe five chapters for this story in total, but I could be off with that count, and it could be more or less depending on where the words take me. Also, reviewers get cookies!