The episode title is taken from the giant question mark in the middle of the blacklight map. The episode is not called "Question Mark", simply just the symbol "?".
Ana Lucia returns in a dream sequence.
Eko's fake passport no. is 223652. His date of birth is 23 August 68. The passport issue date is shown as 16 April 04 and the expiry date is shown as 15 April 14.
In Locke's dream, he walks with a limp (as Eko) just as he would do currently with his injured leg.
Richard Malkin, the father of Charlotte Malkin, is the same 'psychic' that Claire went to see in Raised By Another
back in season one.
Station 5 is called The Pearl. Dr. Marvin Candle from The Swan orientation video appears in The Pearl orientation video but states his name as Dr. Mark Whitman.
As Eko talks to Charlotte Malkin at the airport and he becomes increasingly angry, Libby passes by and asks if everything is alright.
This episode marks the
Eko: I'm building a church.
Ana Lucia: Now why the hell would you wanna do that?
Eko: 'Cause I was told to.
Ana Lucia: Told to by who?
Eko: I was just told. I think it was in a dream.
Ana Lucia: A dream like this one?
Yemi: Hello, brother.
Eko: Yemi! Forgive me, I should have listened to you, you were right...
Yemi: Shhh shhhh shhhh shhhh. The work being done in this place is important, Eko. It is more important than anything. And it is in danger. You must help John. He has lost his way. You must make him take you to the question mark.
Yemi: And Eko... bring the axe.
Caldwell: I've got some friends in Los Angeles. I could get you on with them.
Eko: Doing what?
Caldwell: You know... stuff.
Eko: Monsignor, with all due respect, I cannot do what you have asked.
Monsignor: Why not?
Eko: Because I do not believe what this woman says.
Monsignor: Why do you think I chose you?
Locke: What the hell are you following?
Eko: Where is the question mark?
Locke: The what?
Eko: The question mark, John. Where is it?
Locke: You know what? You keep chasing after your own shadow, I'm going back.
Eko: I know you do not want to show me... but you must.
Locke: No, I don't have to show you anything.
Eko: Then I'm sorry...
Locke: You hit me? Why did you...
Eko: Because you were being difficult.
Locke: Are you insane?!
Eko: She wants us to go here, John, together. She said this in my dream.
Locke: Oh, of course. A dream.
Eko: Tell me, John. Haven't you ever followed a dream?
Locke: You're lost already?
Eko: Your map is inexact.
Locke: No kidding?
Eko: These landmarks... is this a river?
Locke: No, it's a wavy line.
Eko: And what made it fall?
Locke: Boone. Boone made it fall. Then he died. A sacrifice that the island demanded.
Eko: Excuse me?
Kate: Why would he need me to go with him?
Sawyer: Jacko here knows his heroin's in my stash with the guns. So, I can either show you where it's at or let poor Libby suffer. That pretty much it, Doc?
Jack: Yeah. That's pretty much it.
Kate: I thought you were taking me to your stash?!
Sawyer: Do you have to make everything so damn difficult?!
Hurley: (to Michael) I'm glad you're okay, man.
Eko: And I believe the work you have been doing is more important now than ever.
Locke: What... work?
Eko: Pushing the button.
Locke: That's not work. That's a, that's a... a joke! Rats in-in a maze... with no cheese.
Eko: It is work, John. We are being tested.
Locke: (to Eko) I was never meant to do ANYTHING! Every single second of my pathetic little life is as useless as that button! You think it's important, you think it's necessary? It's nothing, it's nothing. It's meaningless. And who are you to tell me that it's not?
Charlotte Malkin: He says you were a good priest.
Eko: Who says that?
Charlotte Malkin: Yemi.
Eko: Speaking about my brother is not a joke so you should be very careful what you say next.
Charlotte Malkin: I saw him when I was... between places. He said that you would come and see me, he said that even though you were pretending, you were a good man.
Eko: Who put you up to this? Did you father tell you to do this?
Charlotte Malkin: He wants you to know that he will see you soon. He said that even though you don't have faith in yourself, he has faith in you.
Charlotte Malkin: (to Eko) He has faith in you. One day, you'll believe me.
Eko: I believe the work being done in the hatch is more important than anything. If you will not continue to push the button, John... I will.
Hurley: (to Libby) Hey. It's Hurley... Hugo. (bursting into tears) I'm sorry I forgot the blankets. I'm sorry I forgot the blankets.
Libby: (struggling to speak) Michael...
Jack: Michael? He's okay. He made it, Libby, it's okay, it's alright.