'''WARNING! THERE MAY BE UNMARKED SPOILERS!'''
* BaseBreaker: The first dialogue confirmation that Time Lords can change gender split fandom down the middle between those who feel the Doctor should at some point become a woman and those who feel the Doctor should remain male (in particular by those who support romance between the Doctor and his various female companions). Debate over this has continued ever since the episode aired, only intensifying after the longstanding male adversary The Master regenerated into a female version.
* CompleteMonster: House, the [[GeniusLoci sentient Asteroid]], is a creature that has butchered hundreds of Time Lords unlucky enough to land on his surface and stitched their bodies into subservient playthings (also took over the mind of an Ood to act as a servant), then hijacked the TARDIS for use as a new body, leaving the Doctor behind to die on the collapsing remains of his old body - and condemning its playthings to die without his influence, to boot. House then decides to use the Doctor's companions Amy and Rory as its new toys, forcing them into the labyrinth of the TARDIS corridors, torturing the two of them with nightmarish illusions, and taunting them with its catchphrase: "Why shouldn't I just kill you now?" House is a being that operates solely according to its sadistic principles of amusement and enjoys torturing whoever is unlucky enough to fall into its grasp. Death might be certain, but House makes certain that when the end comes, its victims will wish for death.
* CrowningMomentOfAwesome: The TARDIS laying the smackdown on House.
--> '''Amy''': Did you wish ''really'' hard?
* CrowningMomentOfHeartwarming: All the Doctor/TARDIS stuff.
** Amy has to think of the things that each part of the password represents. For "Delight", she recalls her wedding with Rory.
** "I ALWAYS took you were you needed to go!" The Tardis confirms in one line what some Whovians have suspected for years. But more importantly, she establishes that she and the Doctor have the same heart as well as an adventurous spirit. Just like he cannot help but involve himself when someone needs his help, she cannot help but send him to the places in need of him.
* NightmareFuel: Okay, let's skip right over whatever it was that was supposedly happening to Rory during those millennia he was trapped alone inside the TARDIS (although the phrase "They come in the night. They come every night and they hurt me," is right up there with the scariest lines in the whole show). What about the cabinet that was absolutely crammed full of recordings of the terrified last cries for help of dozens, maybe hundreds of Time Lords, none of which were ever answered?
** And if that's not scary enough for you, we have a completely sadistic monster in charge of an infinite maze of corridors he can bend and shape at will and dozens of ways to kills those trapped within.
* TearJerker: The TARDIS' goodbye -- and in-universe to boot.