"You don't really want to do that do you?" Asked the Doctor halting the Dalek's war cry.
"YES. YOU ARE AN EN-EM-Y." The Dalek screeched in reply. "YOU MUST BE EX-TER-MIN-A-TED!"
"Well, ummm, yeah, you see that's where you're wrong," the Doctor said, very subtly reaching for the concoction in his pocket. He pulled it out. "Because I have this."
The Dalek just looked at him. Or at least that's what the Doctor could sense; the eye stalk looking straight at his face.
"I'm sorry," he said, chucking the mixture at the Dalek.
It screamed as he metal casing began to melt away, revealing the Dalek underneath. It began to bubble as the sunlight hit it and the Doctor backed away the way he'd come; back towards Martha.
"You killed it," she breathed quietly, staring at the Dalek.
The Doctor continued walking past her and she turned to follow him after a minute. He stared straight ahead dark eyed, stuffing his hands deep into his pockets.
"I did what I had to," the Doctor replied, regretting his actions already. "The Dalek's destroyed my home, my family, my friends and… and Rose Tyler."
"Rose Tyler," Martha whispered to herself following him. "It always comes back to her."
"Yes, it always comes back to her," the Doctor said rounding on Martha. "Because she was the most important person to me. No one on this stupid little planet, none of my companions have ever meant as much as she did!"
Martha looked at him startled.
"Alright," she said walking past him and trying not to let his harshness bother her.
The Doctor rubbed his face before turning and walking after her.
"I'm sorry," he said keeping his voice level. "I'm just finding it hard…"
He stopped and leant against a wall, trying not to burst into tears.
"I guess I'm just meant to always be unhappy," he sighed his voice wobbling uncharacteristically.
"That can't be true," Martha said gently standing in front of him.
"Oh yeah, cause that's why I lose everything I love," he said sarcastically. "You don't know how hard I have to try not to get close to people, and then I do because I think maybe this time it will be different and then they're torn away from me in the cruellest way possible. You realise Rose Tyler is alive and well in a parallel universe but I can't go and see her because it would mean destroying this world and that, and the needs of everyone else have to come before me because I mean nothing. I go round saving this stupid universe and never get one little piece of happiness. That's the curse of the Time Lords for you."
Martha looked at him sadly, wondering what she could say to make him feel better. Somehow she didn't think the saying 'there's always someone worse off than you' would help.
"I have to go," the Doctor said suddenly. "I've been here too long. You'll end up hurt if I stay much longer."
"What if you hurt me more by leaving?" Martha asked quickly, and then put a hand to her mouth as if she didn't mean to say it. "Sorry."
The Doctor looked at her.
"I really have been too long," he said sadly. "This is how it starts. A rocky friendship, you try to get me to open up to understand me, when I finally do, we end up falling in love and then you… I can't go through that again."
He began to walk away but Martha grabbed his arm and turned him to face her.
"Please, let me come with you," she said almost begging. "My life here is so boring, anything is better than sitting at home wondering what might've been."
"Chances are that one day you will die or something equally as bad if you travel with me," the Doctor said trying now to deter himself as much as Martha.
Most of him was screaming not to make the same mistake he did with Rose, but there was a little voice at the back of his head suggesting that maybe, just maybe, it would help him to recover if he had another friend. Of course he'd thought exactly the same thing when he'd first met Rose.
"I've just ducked out of nursing after all that training because I can't cope with it," Martha said. "I'm going to be stuck at home with my parents fretting, my perfect little sister saying 'I told you so' every five minutes and my older brother trying to console me until I get a new job. Please, just let me come with you."
The Doctor looked at her and he could feel himself wavering. After all he'd had companions who had just been friends. Just because he'd felt more for Rose didn't mean the same thing would happen again. For starters he had yet to recover from Rose, so he suspected he wouldn't be falling in love with anyone any time soon if ever.
He stuffed his hands in his pockets and turned, walking away. Martha followed him waiting expectantly for his answer.
"Go home Martha," he said as they turned a corner.
"But-"
"Go home and pack," the Doctor continued before she could say anything. "And tell you're parents you're going travelling with…"
The Doctor stopped and glanced at her.
"Well… I guess we'll explain the whole alien thing when we have to," he said smiling weakly.
Martha grinned and threw her arms round him, giving him a quick hug before running off ahead of him back towards her home pulling out her mobile as she went.
Two hours later the Doctor was stood in the console room tinkering with various bits when Martha opened the TARDIS doors and entered, bag on her back.
"I've got to warn you," the Doctor walked round the console and looked at her gravely, hands stuffed in his pockets. "It's going to be dangerous. Very dangerous. It won't be safe, it won't be calm. But I can tell you what I promise it will be. The trip of a lifetime."