Okay, So I found this when trying to get through the (semi)invisible barrier just for the lolz.
I accidentally went flying to the bottom of the map and instantly died, but after a few tries I landed safe on my feet with the help of noggenfogger.
After trying some more, I realized you could take a shortcut if you are lucky/have skills.
I have it frapsed, but I don't have a movie editing software, and frapsed clips get to big for YT.
Will get it up as soon as I get Vegas or something.
Without the vid, I'll try to explain as good as I can.
Get small using Noggenfogger (might work using Pygmy Oil or even without anything, but I couldn't do it.)
Then jump up to the little mushrooms growing on the wall next to the invisible barrier. You have to get in between the two higher and the two lower mushrooms (may take a while), and then just run and jump towards the invisible barrier, and you should fall through.
Then use your favorite way of slow falling to avoid dying.
Enjoy, and vids are coming.