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.

ROSE: I think what the Doctor's trying to say is you may cut in.

(Rose extends her hand out to Jack to dance.)

DOCTOR: Rose! I've just remembered!

ROSE: What?

(The music changes from waltz to swing - Glenn Miller's In The Mood. The Doctor starts to click his fingers to the music and dance toward Rose and Jack.)

DOCTOR: I can dance! I can dance!

ROSE: Actually, Doctor, I thought Jack might like this dance.

DOCTOR: I'm sure he would, Rose. I'm absolutely certain. But who with?

(Rose chuckles and takes the Doctor's hand. They dance around the TARDIS while Jack watches.)

(Returning to his car, Owen spots a young man.)

OWEN: Bernie Harris.

(He chases him through the streets.)

DOCTOR: Nice balcony. Lovely view. I thought I'd follow you out here, to try and explain.

GUILANA: I think you've done enough.

DOCTOR: No. I've never done enough. It's what you don't understand, what none of you will ever understand. Making your life better wasn't just to manipulate you, but because it was the one thing I can still do. I'd had a bad day, a really bad day. I'd lost a planet and a friend, and it was child's play. Nothing really. And it meant the world to me, because I made you happier. That's all I can do. Do you know what it's like in my head? It's full of the screams of dead friends. Of the guilt, my god, the guilt of every single person I've not saved. Their pictures hung on a wall. Corridor after corridor and on until the crack of doom. My every thought is of them, and how I'll never let it happen again. I can never let on about it, never, because if I do... if I let my guard down for a moment people will see through me, and that won't do. They want to see me as the arrogant bumbler, the annoying genius who'll fix everything. They don't want to know, they don't care, that inside I'm screaming too. I'm so lonely because I've never told anyone how I truly feel. There's no one left to understand. That's loneliness. I'm sick of it all, all the tiny betrayals I've had to make to try and keep this place going, and the millions of lives lost if I have a bad day, just one bad day. Think about that. Everyone has bad days, everyone, but mine are armageddons! Imagine that pressure- no, no you can't. You come at me with your direct gaze and your open questions and your sympathetic tone, you're trying, bless you, but you're a mosquito scratching at a continent. And if that sounds arrogant, then I'm sorry. I spend every sentence trying not to be, but I've a thousand years of dead friends and mistakes in this head, and that's a lot. I can't keep the lid on. Not anymore. That's why I came to see you, because I hoped against hope that you'd see through all my little evasions and games. Because I didn't want you to see the truth... and yet I wanted you to see it so much. The whole of existence hates me and I've not a friend in the universe. That's me. I tried to make your life better, I gave you a family because it seemed like a nice gesture. Like bringing you carrot sticks or cake or crips or whatever your favourite is today, I've lost track, forgive me. It was just a pleasantry, and I can't even get that right.

GUILANA: Stop. A pleasantry?!

DOCTOR: Perhaps the wrong word, forgive me. I don't know anymore. I don't know and I don't care. I feel so small right now, small and scared of what's around the corner. I meddled in your life, and I'm truly sorry. I couldn't help myself. I wanted to do a little good.

GUILANA: Well, you didn't.

DOCTOR: Can you fix it? Can you fix me? Please.

GUILANA: No.

DOCTOR: Oh yes, I'm the Doctor. I'm all bon mots and bonbons, but right now I'm furious! You took away so many people, the unwanted, the unloved, you promised you'd make their lives better- liar! Instead, you threw them into your machines, how cruel of you. And worst of all, you took away Professor Bernice Summerfield. I would say, "If you've harmed her, I'll make you pay" but you have harmed her! So there's that, I've got here too late. And whatever you're going through, if it doesn't kill you, I will hurt you until I feel better and I don't think I ever will! How cruel of me...