Go back to the lowest point and go just a bit lower to reach another world. This one is even bigger than the mainland. And no one without the eye you got in chapter seven could survive. The wire connects a switch and some kind of platform. If you dont follow it you will face hints on activating the switch, but even with the hints in mind, it is very difficult to activate the switch, and certainly under the pressure of knowing this underwater world will flood if you make a mistake. But there is a trick to let the hints make sense.
First Car
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Third Graft
Fourth Airoplane
Fifth Racer
Sixth Indigo
They correspond to the letter of 'CLIFFHANGER'
EDIT: And yes, they would be right if you put in Second F...
If you got it right, you will see four keys. Choose wisely, because if you choose all of them, or a wrong combination, it will most likely slow you down, or even prevent you from winning.