The phrase "Oh the pain...the pain..." is uttered for the first time in this episode and will go on to become Dr. Smith's signature line.
Dr. Smith: I might have known it. You have as much Indian tracking blood in your circuits as I have.
Penny: You can't just stay down here until you die!
Mr. Nobody: What is "die"?
Penny: Well, I--I do think I'm not exactly sure myself. But when someone can't speak anymore, or when someone can't move anymore.
Penny: Mother, do you think just a place could think and talk? Well like here, maybe.
Maureen: Well, maybe.
Penny: I asked Daddy if it's only people that could have brains and he said only very few of them do.
Mr. Nobody: (Penny has just fallen over and been knocked out by the blasting) Penny? Penny! When a person can't talk anymore... when a person can't move anymore... Penny. Please move. Penny, please don't die.
Dr. Smith: It could be that I was mistaken about the possibilities of our finding clay in this area.
Don: Dr. Smith, you've finally said something sensible. But tell me something. Why is it whenever you come near anything, the roof caves in?
Dr. Smith: We all have our good and bad luck, sir. But this time, I was wrong. I concede it.
Dr. Smith: When I think of the value of these rocks back on Earth. Oh, the pain... the pain.
Will: A White Rabbit.
Referencing the 1865 novel Alice in Wonderland by Lewis Carroll (b.1832 - d.1898), whose real name was Charles Lutwidge Dodgson. Alice enters Wonderland by chasing the White Rabbit into his rabbit hole and falling for thousands of feet before landing in the strange reality.