Tegan ran from the London docklands, her head filled with tears and the sound of distant traffic. Above the buzz of engines and indignant horns rose a shriek, a wail that she had not heard for months. She stopped running, for a moment, as the sirens got closer, and standing by the side of the road as the police cars flew past.

They were heading for the docks. Somebody must have heard the gunfire, the screams of people fighting and dying.

She wondered if anyone had seen her, and she could guess what would happen if anyone had. The truth would be impossible, and she would need time to think of a lie that would convince.

She ran on.

This time no monster was chasing her, no one was trying to kill her, no universal terror hunted her here, and yet she still felt the same raw and desperate fear.

She stopped, suddenly, as her thoughts finally coalesced into something solid, something rational that she could understand: she was home and there was nowhere left to run to.

Travelling in the TARDIS had left her with a shattered picture of the universe. Snapshots of societies torn in conflicts; friends that she could never meet again; pain, compassion, love, hope and through it all a thread of death. And as the Doctor vanquished each new evil that the universe decided to throw at him, they would slip away. Move on, and leave behind whatever good that they had done.

Consequences didn't matter because she didn't have to live with them.

It was almost the same in the TARDIS, especially after Nyssa had left. Nyssa, she had missed her more than she could admit. Her friend who had lost everything she had ever known, and yet continued to look kindly upon the universe, had made the decision that winning wasn't enough; she had wanted to build something too. She had made her decision with a precise, rational calm, and Tegan had envied her her sureness of purpose, her confidence in knowing who she was and where she belonged.

And after Nyssa had left, the TARDIS had become her friend. The long labyrinth corridors that had once terrified and trapped her had become a comfort. She found solitude in their depths, the soft hum of their walls her constant companion. Now when she lost herself in them, she would not panic. She knew that eventually the TARDIS would show her the way back. Back to the main rooms of the TARDIS, back to the console room where she would find the Doctor with his head under the console, wires spilling out of the panels as he improved and adjusted and repaired.

She would try to talk to him, sometimes, but it had become more and more difficult. She could argue, worry and complain, yes, but what she had wanted to do was talk. It had been a long time since she had felt able to do that. The Doctor had seemed unable to understand her worries, her fears and uncertainties at the worlds that she was forced to confront, because she didn't know how to tell him. His smiles and kind words were little comfort when she lived afraid and angry at the universe, with her only stability an alien environment that she accepted only because of its familiarity.

Her way of life was a cage, her respites alien worlds, and her return to Earth had offered her an escape.

She had taken it, leaving the TARDIS as suddenly as she arrived. No talking, no explanations, no apologies. That wasn't what she had wanted. She had wanted the freedom of home, to break away cleanly, but as she watched people pass her: ordinary people with ordinary lives doing ordinary things, she knew that she wasn't one of them. That she never could be one of them again.

She had made a mistake.

But the Doctor wasn't coming back.

She was alone.