you have to wait until you pick up the rcp120 before you can destroy the data. this is in contrast to the n64 version, where obviously you can destroy it right after saving the hostages on the second floor.
also to receive the devastator only one hostage can die. the hologram room hostage dies nearly 100% of runs if you just open the door, and one of the firing range hostages typically dies as well. and, even if both firing range hostages live, if you only open the hologram room door but don't save the hostage, objective two will complete too late and carrington's messages delay at the end and waste about ten seconds.
i think he's referring to the ramp right at the beginning of the level. that's what i was talking about, anyway.