Near the Goal
After entering the tunnel below where the corpse of the giant being was, Minos let his body slide down the area's walls, which followed the shape of a giant slide.
This tunnel took him directly to an alternative exit, which seemed to be building as he descended at great speed.
The constructions on that island could change, and this was happening right in front of Minos as he saw the tunnel he had passed through earlier changing to take him off that island.
As he descended at great speed, Minos saw water appearing in his path, noticing that the invisible 'dome' from earlier had disappeared with the disappearance of that mummy.
He was not surprised by this and soon began to swim back to where his yacht was.