DOCTOR: Every great decision creates ripples, like a huge boulder dropped in a lake. The ripples merge and rebound off the banks in unforeseeable ways. The heavier the decision, the larger the waves, the more uncertain the consequences.

DOCTOR: You can always judge a man by the quality of his enemies.

DOCTOR: Ace, give me some of that Nitro Nine that you're not carrying.

MIKE: I found him wandering the streets.

DOCTOR: I was not wandering the streets. I was merely contemplating certain local cartographic anomalies.

ACE: We did good, didn't we?

DOCTOR: Perhaps. Time will tell. It always does.

DAVROS: The Daleks shall become Lords of Time! We shall become all-

DOCTOR: - Powerful. Crush the lesser races. Conquer the galaxy. Unimaginable power. Unlimited rice pudding, et cetera, et cetera.

RACHEL: Why are two Dalek factions fighting each other.

DOCTOR: Ace.

ACE: It’s simple, isn’t it. Renegade Daleks are blobs.

DOCTOR: Blobs?

ACE: Imperial Daleks are bionic blobs with bits added. You can tell that Daleks are into racial purity. So, one lot of Daleks reckon the other lot of blobs are too different. They’re mutants. Not pure in their blobbiness.

DOCTOR: Result?

ACE: They hate each other’s chromosomes. War to the death.

DOCTOR: Your species has the most amazing capacity for self-deception, matched by only its ingenuity when trying to destroy itself.