- In the entry hall
- In Ryan's office (offline)
Rapture Central Control is basically just hurry up and wait. There are several pauses.
Ryan makes his big "a time to destroy" speech (during which the door to the next room is blocked by an invisible barrier). Atlas follows up with a radio message.
Ryan's speech is on a timer. You can't get past the barrier before the timer ends. But Altas's radio message is triggered at the end of Ryan's speech. And it can block the door in the "Would You Kindly" room. So diary skip Ryan's speech then loot the room.
Have a wrench or grenade ready to knock out the grating.
The "Would You Kindly" room's door is locked for a bit to complete Atlas' radio message (unless you skip it).
The whole "a man chooses" sequence - first the conversation through the glass, then the conversation face to face.
There's no known way out of the "man chooses" sequence. It plays even if you you play other stuff on the 360. Be at the door when it opens.
Atlas's speech and Fontaine's speech
Radio skip both Atlas's and Fontaine's speeches: "Continue to Core" for the first, "Override Self-Destruct" for the second. The 2nd speech waits for any playing audio to finish, and the end of the level does too.
Useful Death Warps
The only one that might've been useful - between Ryan's speech and Fontaine's, back to the main hall - is impossible. You are invulnerable during this time.
You can't back out of the "man chooses" speech, like with Cabbage's trick in Smuggler's Hideout, it seems like. I think an invisible barrier goes up as you hit the trigger. And the radio selection screen isn't accessible
"You can play radio messages and diaries while Ryan is making his little speech before he opens the door [on the 360], but all it does is make him continue doing his animation silently if you use a radio message. If you play an audio diary, both voices play at the same time. " -- Cauldrath (You can't even reach the radio messages screen on the PC.)