The simplest fix is to completely close the game and restart it. Some players have reported that the gate will appear open upon the next boot-up.
If a trap door won't open after pulling a lever, try throwing a Chakram and warping through the gate if you have the ability, or simply restart the game to see if the gate resets to an "open" state. prince of persia forgotten sands door bug fix
This bug is triggered if you quit or die in the hallway before the Observatory. To avoid this, always finish the entire Observatory puzzle in one session and ensure no switches are active when you save. The simplest fix is to completely close the