Okay, so... where exactly does this music play? I've done Diadem and haven't heard this music play and have been informed Emergency Missions don't use this music, either. Or has it played before and I just don't remember it?

Sorry if it's not at all related to the story discussion, but since it played in a 3.5 trailer and... it doesn't seem to be playing anywhere in 3.5-3.56, I'm just curious. And will possibly go mad because it sounds familiar, but I don't know why.