If it's the room I'm thinking of.
Go up above there's a switch on a wall somewhere, to be honest the puzzles in this game aren't rocket science, there's always something nearby which is easy to find.
Ok I looked for a floor lever and right near the gate.
Also the first puzzle in there is not hard...the one to unlock the rings and use the claw. I got it first time without checking any websites lol...A first for me...when you consider the possible combinations that was very lucky.