Casey Jones: This is great. First it was The Farm That Time Forgot and now this. Why don't I ever fall in with people who own condos? Probably hard to get good maid service in a sewer. Maybe you guys should try Roto Rooter, huh?
Michelangelo: God, I love BEING A TURTLE.
Tatsu: Go... play.
Raphael: I do hope there's more o' them.
Donatello: We were awesome.
Michelangelo: Yes, Dudes and Dudettes, major-league butt-kicking is back in town.
Splinter: Who are you?
Casey Jones: Casey Jones, a friend.
Splinter: All fathers care for their sons.
Donatello: Good thing these guys aren't lumberjacks.
Michelangelo: No joke. The only thing safe in the woods... would be the trees.
Chief Sterns: We are presently executing a plan of redeployment that will minimize response time while maximizing coordination between patrol units and a decentralized networking scheme.
April O'Neil: I'm not sure I understood all of that, Chief Sterns. Would you mind repeating it, in English, perhaps?
The Shredder: There will be no mistakes this time... I go myself. And the rat - kill it.
Tatsu: Yes, Master.
April O'Neil: And then there's Casey Jones, a nine-year-old trapped in a man's body. He might be cute except for that pigheadedness.
Chief Sterns: All right, I want some answers. Now what in God's name happened out here tonight? Somebody better talk to me.
Gang Leader: Check out the East warehouse over on Lairdman Island. You'll get your answers there.
April O'Neil: So, what do you guys like on your pizza?
Michelangelo: Oh, just the regular stuff: flies, stink bugs... It was a joke.
Donatello: You're a claustrophobic.
Casey Jones: You want a fist in the mouth? I've never even looked at another guy before.
Tatsu: Never lower your eyes to an enemy.
Splinter: I am proud of you, my sons. Tonight you have learned the final and greatest truth of the Ninja: that ultimate mastering comes not from the body, but from the mind. Together, there is nothing your four minds cannot accomplish. Help each other, draw upon one another, and always remember the power that binds you. The same is what brought me here tonight, that which I gladly return with my final words: I love you all, my sons.
Tatsu: Ninja... vanish.
Answer: Most likely to kill Shredder and make sure that there would be no way to come back but, as seen in the sequel, Shredder does return.