One of the 'dungeon' themes from ECO, used across various seasons/books/whateverIAmCallingThemJesusThisThingWillNeverGetFinishedSomeoneKillMePlease. Originally, I had used it for what became the train scene in season 1, as well as the Temple of Slumber in season 2.
My main inspiration was Motoi Sakuraba's work on the Star Ocean Series, although it might be a touch hard to tell. <_>;