Of course we cant risk to build a teleporter on the surface because of our enemies. So you have to walk the way back through the maze. But since you know the right way it shouldnt take very long.
Two centuries ago, I created this teleporter so that we can do our experiments much more faster.
Now you only step in the teleporter, that is located near the resting rooms and you will be teleported on the surface.
In the old days we had to walk all the way back out of the maze and then in again.