A/N: For those Torchwood fans that aren't Dr Who fans you can easily skip this without loss, but my advice is to become Whovian :)
Spoilers: Season 3 of Dr Who
Beta-ed: TattoedLibrarian
Martha watched Jack as he ran off and she laughed at the prospect of him being The Face of Boe, the richest and oldest thing alive that could communicate telepathically, and teleport without effort, and the thing that would die in the end. Watching Jack she suddenly knew that seeing his death wasn't a sad event, it was a relief after a long existence, but also it was a gift to them so they would know how he ends, so they wouldn't worry. Because Martha did worry about Jack, she felt like she'd known him forever, and he quickly grew on her. She would miss him, as she would miss the Doctor, because she knew that Jack did the right thing, he went out, and she would too.
"You too" Jack said to her referring to her romantic feelings towards the Doctor. Martha watched the Doctor grow old before her eyes, but that didn't diminish the feeling she had towards him. Then she knew that nothing that the Doctor could do would ever disillusion her, she had to go to get it over with. She had thought about the Doctor for too long now, it was time to think of herself, and those around her, because if she lingered a bit longer around the Doctor the next time she came back she would be even older than she was now, her sister would look like child to her, she almost did now. She gave years to the Doctor stranded on the strangest of places. She even worked as a maid for him, putting up with discrimination while he ignored her to fall in love with another blond; finding out that Rose was blond was no surprise to her. Even when he was human in 1913, he didn't look at her. Then there was that time she worked in a shop to support him in 1969 while they waited for some random strangers from future to rescue the Tardis. The cherry on top was walking all across the Earth for a whole year. She was fit as never before, she felt like a soldier after everything. To be focused so long on the task, and to follow orders changed her. She learned how to go beyond her comfort zone and to ignore her hearts aches, and her body's needs, she learned to let go what she wanted. That's how she finally let go of the Doctor and accepted that it would never be, he would never turn his eyes towards her and look at her like he did that schoolteacher Joan he's almost gotten married to. Or even the way he looked at the dying Master in his arms, it was bare need in his eyes, a need for something that died, and that never dies, she knew then she would never be enough, and that was what she wanted, to be enough for someone.
Now she was more than five years older than her timeline, her sister had been three years younger, and now she was seven years younger, and that is just counting linear time in numbers, not the experience she could hardly share with them. Well maybe now she could, they've tasted the fear and the choices. It was so weird to share it all with her brother whom had forgotten it all and was now younger then she was. The look of horror and confusion in his eyes showed her what she would become to them again if a bit more time passed by.
She had no time to wait for the Doctor to grab a new life boat; time "We missed the election day" was the only thing she could think of when they landed back home escaping in a nick of time from the end of the universe. She felt guilt and sadness because she missed tea with her mother, because she had waited in vain for Martha, unable to reach her, worried and alone, feeling rejected. That's when she realized that the Doctor wouldn't be able to get her back exactly when she took off, not only literally in that moment of time and space, but emotionally, time passed by for her, and she had changed. Now it was time to go.
And she did, she did it, she got out, but as she was leaving the Tardis she realized that she didn't feel complete, she left things unspoken and that was just wrong after everything. After all she had spent years with the Doctor and he deserved to hear a piece of her mind, and she deserved that he acknowledge her at last. That's why she tossed the phone to him, to keep a string on him, she knew he didn't do that, but she'd earned it. If he couldn't give her the feeling she wanted, the feeling she was unique and special, at least he wouldn't leave her with that feeling of a changed number and address, he had better answer her when she called, she deserved that much.
With that, she left satisfied. The Earth was restored, Tom Milligan was alive, the professor and her son were safe, Jack was in Wales just a phone call away, even the Doctor was a phone call away, and in the house was her family alive and safe, and they understood her now, they understood what the Doctor's time did to her, and that the Doctor was not the one to blame, that there were monsters out there. Martha only regretted that she couldn't fight them anymore, she had gotten used to that. She was going to miss the adrenalin, running and being so fit.
Strangely, I wasn't very into Martha, not until I watched fan video of Dr Who I think it was called Dr Who musical, and her song was Fuck you from Lilly Allen, it was only then when I finally got her point of view.