It's the one thing they all had in common. He'd seen it in Barbara, in Ian, Jamie, Victoria, in Liz and Jo and Sarah Jane, Leela and Nyssa and Tegan, Adric, Turlough, Melanie, Ace, Rose and Jack, and yeah, even Donna. He'd see it again, over and over, and he saw it in Martha Jones. That inquisitive, spark, the sense of openness, the wonder and courage...the ability to see him as more than a knight in shining armor.

But he can't just go taking people on willy-nilly, plucking them from Rassilon-knows-what. So he stops himself from waving her over and inviting her on a trip, even after the hospital lands safely back on earth.

But when, by pure chance, mind you, he witnesses the little scene outside the nightclub...well, what kind of doctor (with or without a capital) would he be if he didn't try to get her out of what was clearly an unsafe environment? He has to get her away, at least for a little bit...or maybe more.

After all, that quality is rare. She deserves a chance, this would be Doctor Martha Jones.