And when the end finally comes for him, it is so different from the rest, from the Second Doctor’s forced regeneration, from the Seventh Doctor, pleading with human doctors not to administer the electric shocks that would kill him in an attempt to save him, from David Tennant’s famous last words of “I don’t want to go”. Rather, the Ninth Doctor accepts his death with the air of a man who has been waiting for death at every corner, and has made peace with it. Certainly, his main motivation is to save the life of the woman he loves, but there’s a sort of strangely happy resignation to it. He faces his death as a man ready to let go, ready to move on, ready for a change, change he would find in his new form, younger, friendlier, and less haunted by the past. [source]
lady christina: those things are gonna turn the entire earth into a desert. so why exactly are you smiling?
ten: the worse it gets the more i love it
lady christina: me too.
stranger, i’ve known you for so long,
i found you lost with a compass in the fog