"Everybody lives, Rose. Just this once! Everybody lives!"
There's a joke going round that Steven Moffat was true to his promise here, and that it was only this once everybody got to live. While Moffat isn't really the character-killer that he's made out to be, that was never what made this moment quite so good anyway. So many of the Doctor's adventures result in at least one death and it must get tiring for the charactet at times. His excitement over a having an adventure where everyone gets to live - in the middle of World War II, no less - is simply great to watch. Again it's Eccleston's performance that pulls the true brilliance out of this moment. His excited energy rises and rises, culminating in near euphoria as he throws the nanogenes towards the many infected people who have crowded around the scene. It's so catching that you can't help but smile along with him, and shout the quote if you know it, and it's truly heartwarming at the same time. The idea to have such a story in the middle of a World War, and with a Doctor still stricken by grief from a war he couldn't win, was a brilliant one. Beautiful moments like these are what really make Doctor Who as good as it is. Fans have been lucky to get so many, and this one is up there with the very best.