A/N: Disclaimer, I own nothing. Sigh.
Read, Review and Enjoy! (But not necessarily in that order.)

Push this lever and it's over. 20,000 people…

As The Doctor held the lever with shaking hands, images flashed through his mind. His eyes stared unseeing at the pods control panels. Donna, beside him, shaken, horrified, and afraid, was finally beginning to understand what she could never fully comprehend.

Even now, children chased dogs through narrow streets. Mothers washed togas and stolas, and men prepared dinner arrangements as shopkeepers shouted their wares.

Each with a bright future; not with the Pryovile alternative, but with the proper timeline, the proper universe.

Every waking second, I can see what is, what was, what could be, what must not.

The scenes flashed by more quickly, a child and her brother, playing with a dirty ball. Later, the girl arguing with her mother as the boy learned politics in the other room. Faster and faster, marrying, families, death. A new person, a slave, freed at last only to be captured and sold again in Rome. A soldier gone to join the Roman army, dieing in battle years later. A young mother bathing her son, then a family of six. A shopkeeper, counting his earnings outside, to be robbed in the following months. A boy, working on his alphabet as others played, growing to be a prominent orator.

Wise old men, untroubled young children, hopeful youths, world weary wives, ambitious suitors; they all blazed before his eyes. He followed each line, each life as it went. Suddenly, it all rewound in a second. Each life now ending in a bright flash of white. Then the Darkness fell, burning and merciless. Pain, death and terror. For every one.

Then him. The Doctor saw himself. Hands in the pockets of his suit coat. Unmoving with cold, hard eyes, he stood alone at the TARDIS consol. He stared into the empty void that was his own eyes. No friendship. No hope. No mercy. No love. Nothing. But as the silent alien stared, something changed.

The image faded into another. Still himself in the TARDIS, but no longer with a distant, unfeeling gaze. His eyes were bright with emotion. Sadness, joy or something else entirely, it was difficult to tell. And he was no longer alone. Donna stood beside him with a small smile, Martha with a confidant stance, Jack behind them, his long coat waving slowly back and forth. Right beside the future Doctor stood a woman, blond and beaming.

Warm hands touched his, and the images faded. The dark, red lit pod came back into focus. The lever solemnly still. His hands still shaking but less with the weight of the others on them. He looked up to meet the tearful eyes of Donna. Her hands rubbed his and she looked at him with silent sorrowful support in her eyes. She may never truly, fully, understand. But she was there and she would try.

Together, they pushed the lever.

Welcome aboard.