The Doctor: So, physics! Physics, eh? Physics! Phyyyysics! I hope you're getting all this down! The Doctor: K-9! Rose Tyler, Mickey Smith, allow me to introduce K-9! Well, K-9 Mark III, to be precise. Rose: Why does he look so... disco? The Doctor: Oi! Listen, in the year 5000, this was cutting edge! Rose: I thought you and me were— Well, I obviously got it wrong. I've been to the year 5 billion, right, but this... Now, this is really seeing the future. You just leave us behind. Is that what you're gonna do to me? The Doctor: No. Not to you. Rose: But Sarah Jane. You were that close to her once, and now you never even mention her. Why not? The Doctor: I don't age. I regenerate. But humans decay; you wither and you die. Imagine watching that happen to someone that you— Rose: What, Doctor? The Doctor: You can spend the rest of your life with me, but I can't spend the rest of mine with you. I have to live on. Alone. That's the curse of the Time Lords. Brother Lasar: Our time has come, my brothers. Today, we shall become...gods! Sarah: I saw things you wouldn't believe! Rose: Try me. Sarah: Mummies. Rose: I've met ghosts. Sarah: Robots. Lots of robots. Rose: Slitheen. In Downing Street. Sarah: Daleks! Rose: Met the Emperor. Sarah: Anti-matter monsters! Rose: Gas-mask zombies! Sarah: Real living dinosaurs! Rose: Real living werewolf! Sarah: The Loch Ness monster! Rose: Seriously? Mr Finch/Brother Lassar: You... bad dog! K9: Affirmative!