From Halopedia, the Halo wiki
This should eject the player from the map's boundary, allowing the player to fly out into the sea. However, gravity is still a factor here, and the player will eventually go under the bottom of the map, being automatically killed. The usual "Return to the battlefield" prompt will appear, giving 10 seconds to return to the boundaries before dying. This can also be performed going around the wall, and over the cliffs on the opposite side from the wall.