lol, your not an idiot- I think I know what your talking about. But for the life of me can't remember exactly what your supposed to do.
Does the room with the moving teleporters have triggers on the ground that shoot you back down to the basement? You need to get through the room, or rooms and then place all the armour pieces on the entrance display thingy.
Damn, I'm no help- sorry! I haven't played through the SCD version in a LOOONG time, but I might be able to dig up a VCR tape I made (1997 ish) of the last stage and ending, if I look around.
Playing the SNES or PC versions if I remember correctly were pretty similar, just instead of one GIANT dungeon the TG version had it as more seperate mini dungeons, which I kind of prefer actually.
Good luck, tell us if you figure it out!