A locking mechanism for a door panel to be positioned within and out of blocking relationship with an opening. Mechanism includes a deadbolt rotatably connected to the wall and having a curved configuration and a locking bracket connected to the door panel. The locking bracket extends from the door panel in an angular direction with respect to a plane of door panel. With door panel in a closed position and deadbolt in a first position, the locking bracket extends through the curved configuration. Deadbolt is in blocking relationship with the locking bracket in a direction along a plane of the door panel and is not in blocking relationship in a direction along the locking bracket. With door panel in closed position, deadbolt is in a second position not in blocking relationship with the locking bracket permitting door panel to move in a direction along a plane of the door panel.