Phazon Infusion Chamber

The Phazon Infusion Chamber is where Metroid Prime becomes infused with phazon. Samus disturbes him from his slumber and Prime battles her. Metroid Prime breakes a whole in the wall and jumps down it. Samus follows him which leads her to Subchamber 1. Once Samus defeats Metroid Prime in Subchanber 4, he knocks a whole in the wall to his right hand side and falls down it. It leads to Metroid Prime Lair.