Turn Left (Chances)
Donna's adventure truly terrified her, but I think it's safe to say it scared me far worse.
Because, sifting through her memories, I saw so many opportunities…
Because without Donna, there is no doubt in my mind that my Doctor would have died a long time ago. Even if someone else had saved him in that Racknoss incident, without her advice to "find someone," I don't think he'd have agreed to take Martha. And even with Martha, he still seemed to have a phsycotic deathwish all of 2007. He let that Plasmavore suck away his blood. He took an incredible amount of liberties shortly after meeting Shakespear. He jumped from car to car over and over again on New Earth.
There were so, so many chances he would have died. Thank you so much Donna. Thank you for saving him.