After defeating Mother Brain, a 60-second self-destruct sequence will begin. You must escape Zebes before the timer runs out! The path back to your Gunship in Crateria is now open and generally straightforward, but you'll need to move quickly and efficiently. Don't stop for enemies unless absolutely necessary, and use your Screw Attack to clear paths if you have it.
The escape route will take you through a series of vertical shafts and horizontal corridors, often requiring quick Morph Ball maneuvers and precise jumps. There are no power-ups or hidden items to collect during the escape, so focus solely on reaching your ship. If you're low on energy, try to avoid taking damage, as there are no energy refills. Reaching your ship before the timer hits zero will trigger the ending sequence and complete the main story.