"It isn't like I haven't torn through dimensions before," she reminded him, feeling a little silly at bringing it up. Because it wasn't supposed to be done. But she had. Because she could and she'd needed to and this place needed her. And being trapped back in that world? Where she was still just a weak woman content to be someone's wife and, with any luck, a lead on the sales floor? She couldn't. "It isn't like I don't know where to find my connections. UNIT would have still existed in that world. I doubt Torchwood would have, but they would. They were around long before me."
It had taken time, but she'd been able to start piecing together what might have happened and what wouldn't have. Not just in the world she'd ended up in, not in the one his other self had come from, but in plenty of different dimensions. What if the TARDIS (okay, and her) hadn't given Jack the ability they had? What if she hadn't gone back to Satellite Five at all? What if he really had left her back in the eighties like he'd threatened to? What if, what if, what if. Those what ifs were the things she dealt with on a daily basis during her time traveling dimensions. And in the last two weeks, they'd reared their ugly heads all over again.