That kind of sounds like a strategy to trigger lucid dreaming. I've heard that if you envision a specific thing while falling asleep, like for example the StarCraft menu screen, then it will appear somewhere in your dream. When it does, it's supposed to sort of jostle you into consciousness but not wake you up.

It seems that what this person's friend did with his free will in dream land is nope right out of there. He could have turned that nightmare into something awesome though!