Sensei Greg decided to close down the dojo since the danger of giving people magical powers was too great and the only students left were Justin, Nanase, and Elliot. The dojo was the scene of the battle between Sensei Greg and Grace on one side and the summons of Dex on the other - apparently, it happened just when Greg was moving out. Immediately before the battle, the Taurcanis Draco crashed up through the roof and created a hole in it.