What's your interpretation of the ending of Akira?

My theory is that since the power of Akira simulated, or replicated, the birth of the universe, then the girl was saying that they could possibly return since the universe has already been born; or that the universe goes through cycles of life and death, therefore, they would be able to return at the next birthing. The ending was kind of confusing to me, so any other theories to clarify things would be most illuminating.