Oh dear, you didn't really think about that did you? Your wish is granted, and the room is filled with custard. Only trouble is, you are now unsure of where the door is, and even if you did know, you are still tied to the chair. Being as how the custard level is way up over your head, you are also drowning horribly.

'Mggt gmmf schlmmt rfft.' You say.
Then you die. Famous last words if ever I heard them! FIN.