After the battle with Golbez where everybody dies, they say that if you have Rydia use Warp, you will be back in the Crystal Room. With the crystal still in there. And if you get it, when you get to the Sealed Cave, Kain will tweak before you get into the cave, thus saving you a tremendous amount of time and items and whatnot, and, best of all, you don't have to fight those friggin' Trap Doors, or that damned Evil Wall. I hated that wall. But anyway, they were right.