Subchamber 4 is a room in the Impact Crater in Metroid Prime. It is the fourth and final battle within the subchambers of the crater, where Metroid Prime in its exoskeleton form is fought. In this subchamber, Metroid Prime will use all four beam color attacks, randomly switching between them at will, making it more difficult to cause damage quickly. When damaged enough, it will fall through into Subchamber 5 and down into the Metroid Prime Lair.