HAH! I knew it.
If you watch the beginning of the game, Master Xehanort rigs the exam by using darkness to screw with the orbs of light. Eraqus doesn't notice it's MX's doing and gets angry, and after the exam is over and he notice's Terra's darkness he reprimands him and chooses Aqua as the next master.
If you watch the beginning of the game, Master Xehanort rigs the exam by using darkness to screw with the orbs of light. Eraqus doesn't notice it's MX's doing and gets angry, and after the exam is over and he notice's Terra's darkness he reprimands him and chooses Aqua as the next master.