Translation by Mors:

When walking down the spiralling staircase, the dialogue that appears is the same as the one in the flashback Mickey has before the 1000 Heartless brawl (Xehanort asking permission for his experiments, which Ansem denies him). Then the well-known lines from the trailer.

In The World That Never Was:

Vexen: Zexion! Zexion!
Zexion: What’s all the fuss about?
Vexen: Where’s Xemnas?
Zexion: At the usual place.
Vexen: The “Room of Sleep”?
Zexion: If it’s urgent, why don’t you go and see?
Vexen: Stop joking around! I will await his return. I must. This is what happens when we need him and he sleeps. Now, of all times…
Xigbar: I’m not so good in that place either. How about you, mister Zexion?
Zexion: What are you doing, eavesdropping like this? The mission assigned to you and Xaldin was to look for new members. You shouldn’t be able to afford wasting time around here.
Xigbar: I’m doing enough work, already! Found another one just yesterday. I think his new name is “Mar-” something or other. With this the Organization now has 11 members. That’s quite a number. And so just for today I asked Lexaeus to cover for me so I could take a break… in anticipation of tomorrow’s work, that is.
Zexion: Then please rest fully. I have work to do for today so I’ll be going…
Xigbar: So harsh of you. I just want us to have a little fun talk about, say, Xemnas’ secret. How many years ago was it? People with the blade of keys started to appear and fought great battles. When they were gone, a man who had lost his memories appeared. Xemnas… no… Xehanort was taken in by Ansem around that time, was he not?
Zexion: What of it?
Xigbar: The “Room of Sleep”… the underground laboratory where we were studying the darkness within people’s hearts, the place which Ansem ordered us to seal-away… The first thing Xemnas did when he got rid of our wise yet bothersome leader was to release the seal and make that room in the depths of the laboratory. After that he frequently went down there and I could hear him talking with someone. Isn’t that odd? Xemnas is supposed to be in there alone.
Zexion: It seems you really enjoy eavesdropping.
Xigbar: I couldn’t hear what they were actually saying. And so I feel preoccupied. You’re interested too, right?
Zexion: I simply want to concentrate on my assignment. You too should concentrate on your real mission and collect more members. We must hurry with the preperations for our new quarters… 11 Organization members is not enough.
Xigbar: Our new quarters… oh, Castle Oblivion, right? What does Xemnas hope to achieve by using that?
Zexion: We’ve been told that-
Xigbar: There’s a reason, one that hasn’t been told to anyone. With the “Room of Sleep” comes the “Room of Awakening”, the other place. That is what he is seeking; that room, which was not made by Xemnas. Perhaps that is where the other… “friend” is.