BARBARA: We failed.

DOCTOR: Yes, we did. We had to.

BARBARA: What’s the point of travelling through time and space if we can’t change anything? Nothing. Tlotoxl had to win.

DOCTOR: Yes.

BARBARA: And the one man I had respect for, I deceived. Poor Autloc. I gave him false hope and in the end he lost his faith.

DOCTOR: He found another faith, a better, and that’s the good you’ve done. You failed to save a civilisation, but at least you helped one man.