LADY ADELA: I thought I’d buried my past here.

DOCTOR: None of us can do that. The past isn’t a separate part of us, a photograph album we can leave in a drawer and forget about. Every decision we take, every thrill we experience, every disappointment we face – they make up who we are. Lose the past and you lose yourself.

LADY ADELA: That’s precisely what I want: oblivion.

DOCTOR: Forgetting something doesn’t stop it hurting: it makes it worse. Unattended wounds fester. I lost someone very dear to me today, but I won’t forget her. If you love someone, you need to remember everything about them: their face, their voice, the things they used to say. Keep them alive inside you and they’ll never really die. Brave heart, Lady Adela. Brave heart.