MISSY: (as Maggie Smith) I am in charge.

DOCTOR: Well, who's in charge of you?

MISSY: I'm in charge of me.

DOCTOR: Well, who repairs you? Who, who maintains you?

MISSY: I am programmed for self-repair. I am maintained by my heart.

(Missy takes the Doctor's hand and places it on her bosom.)

MISSY: Is everything in order?

DOCTOR: Who maintains your heart?

MISSY: My heart is maintained by the Doctor.