Well, it would be interesting to see what would happen if STF did lose a leg, or if he couldn't come up with the answer. But I might as well take a stab.
Just because of Morpheus's name, I thought it might be the dreamworld/mind and reality? Because they are sort of related or close but at the same time opposites, and when you sleep you usually dream about something related to reality, like your fears or aspirations. So if you have a fear and dream about it, your dreamself might be fighting your fear.
But that's kind of unlikely, isn't it? After all, the answer is too related to his name