When Zuko is asking Katara what she thinks will happen, her fingers are blue.
When Jeong Jeong is fighting against the Fire Nation tanks, he shoots a wall of fire at the tanks moving them out of the way. In the next scene, they are back where they were before.
Into the Inferno is also the title of the third Avatar: The Last Airbender video game that was released in October 2008.
Ursa: I think you're confused. All your life you used fear to control people, like your friends Mai and Ty Lee.
Azula: But what choice do I have? Trust is for fools! Fear is the only reliable way! Even you fear me.
Ursa: No. I love you Azula, I do. (Azula throws her brush at the mirror, which then shatters)
Sokka: Go Aang! Airbending slice!
Azula: (to Zuko) You want to be Fire Lord? Fine…Let's settle this…just you and me brother. The showdown that was always meant to be…Agni Kai!!
(Talking to her hallucination of Ursa)
Azula: Don't pretend to act proud. I know what you really think of me. You think I'm a monster.
Azula: Alright hair, it's time to face your doom.
Bumi: Ba Sing Se, the Order of the White Lotus is here.
Pakku: Here to set you free.
Azula: Is this how you plan to treat your new Fire Lord with tardiness and disloyalty?
Dai Li Agent: The Dai Li would never betray you.
Azula: And I'm sure that's just what you told Long Feng before you turned against him and joined me. You're all banished!
Suki: It's weird to say, but the comet actually looks beautiful.
Toph: Too bad the Fire Lord is about to use it to destroy the world.
Lo: But considering everything that's happening today...
Li: Perhaps it's best if we postponed your coronation.
Azula: What? Which one of you just said that?
(Lo and Li point at each other)
Azula: What a shame. There's only one way to resolve this. You two must duel each other. I order you to fight an Agni Kai.
Lo and Li: We're not Firebenders.
Azula: Alright. Fine. (Points at Li) Lo, you're banished. (Points at Lo) Li, you can stay
Li: But I'm Li, so who's banished.
Sokka (Over the intercom): Attention crew, this is your captain speaking. Everyone please report to the bomb bay immediately, for hot cakes, and sweet cream. We have a very special birthday to celebrate.
(In the bomb bay)
Quinn Lee: Hey, I'm Quinn Lee, I work up in communications.
Engine Worker: Oh, Hi. I work down in the engine room. That's probably why we've never met before. Big airship, you know. (Quinn Lee laughs) Yep.
Quinn Lee: Do you know who's birthday it is?
Worker: I can't believe the captain remembered my birthday, he really does care.
(Hatch opens up, everyone falls into the water.)
Engine Worker (After resurfacing): Happy birthday.
Ozai: After generations of Fire Lords failed to find you, now the universe delivers you to me as an act of providence.
Aang: Please listen to me, we don't have to fight. You have the power to end it here and stop what you're doing.
Ozai: You are right. I do have the power. I have all the power in the world! (Ozai shoots two huge fireballs from his hands and one from his mouth)
Ozai: You're weak, just like the rest of your people. They did not deserve to exist in this world, in my world! Prepare to join them. Prepare to die!
Sokka: Good work, Toph. Time to take the ship. Take the wheel.
Toph (sarcastically): That's a great idea. Let the blind girl steer the giant airship.
Sokka: I was talking to Suki.
Toph: That would make a lot more sense.
This episode aired along with "Sozin's Comet (1): The Phoenix King", "Sozin's Comet (2): The Old Masters", and "Sozin's Comet (4): "Avatar Aang" as the TV-Movie/Series Finale: Sozin's Comet: The Final Battle.
This episode is available in the Book 3: Fire, Volume 4 DVD, along with, "The Southern Raiders", "The Ember Island Players", "Sozin's Comet (1): The Phoenix King", "Sozin's Comet (2): The Old Masters", and "Sozin's Comet (4): Avatar Aang".
Zuko and Azula's battle may be a humorous reference to the phrase "Fight fire with fire", meaning if you wish to defeat your enemy you must think like your enemy.
When Azula smashes the mirror because of seeing the hallucination of her mother, is similar to how Harry Osborne reacted to seeing a hallucination of his father in Spiderman 2. Both characters' hallucinations consist of one of their parents that does not give them enough love.
Azula's paranoia that stems from her recent betrayal of Ty Lee and Mai from The Boiling Rock has drastically made her insane, which is similar to what happened to Clark Kent from Smallville in the episode called Splinter.