Rose Tyler:  I 've been to the year _ five million _ , but this , this is really seeing the future- you just leave us behind ! Is that what you 're going to do to me ?
The Doctor: No . Not you .
Rose Tyler: But , Sarah Jane- you were that close to her once , and now ... you never even mention her . Why not ?
The Doctor: I do n't age . I regenerate . But humans decay . You wither and you die . Imagine watching that happen to someone you ...
Rose Tyler: What , Doctor ?
The Doctor: You can spend the rest of your life with me . But I ca n't spend the rest of mine with you . I have to live on , alone . That 's the curse of the Timelords .