Prince of Persia: The Sands of Time

This is story related and cannot be missed.

You will know when you are in the elevator because it is a circular type room that (obviously) works as an elevator. You need to use it to take you to the top of this tower where you will eventually find the hourglass.

Enter the room and cross to where Farah is standing, the elevator will then start to ascend. Soon after you will begin to get attacked by a lot of enemies, take care of these however you wish. I found using the dagger to make enemies go in slow motion to be hugely effective here, you can put a few into slow motion and then go concentrate on the others. Also try to make as much use of the two fountains on either side of the elevator, is you drink from them then they can restore your health. I also suggest you stay near or keep a watchful eye on Farah, if she dies you will fail this section and will have to start on the elevator again from the very bottom. Simply kill all of the enemies and reach the top to earn this trophy.