Batman: Arkham-Asylum: Where to go after burning the Formula

After we destroy the formula of Dr. Young, we then need to rescue her. We are in a circular room with multiple floors:

Mission: Rescue Dr. Young from Zsasz in Warden’s Office

After you destroy the formula, you are on the ground floor: Use Grapple to get to the first floor. Here you can find a door which is the way out. Some gas can be seen with this door: and due to this gas, you will enter another dream like world mission : )