Right now I am playing barbarian/monk (31/3) troll and stuck at 50th level of CoC. I've got all four elemental shards with me in my backpack (identified, if it matters), but I don't see Chaos gates or downstairs to proceed. No secret rooms so far. It is just an ordinary dungeon level. I am sure that I miss something, but I don't know what to look for. Is there anything special what needs to be done to actually win the game?