[B.0]my offzone doesn't go to edge

[bludshot]

I am making a map with high up platforms, and then I want ALL the ground around to be offzone water. In the map editor I filled up all the bottom with offzone water to the edge.

But then in the game, you can jump off the high platforms and land on the ground *beyond* the offzone.

Is that just how the game is? Am I supposed to put a wall around the map?