The Shamba-La mandala is a powerful piece of architecture that took about three hundred years to create. Its design, instead of being just ornamental, represents the actual universe itself. The mandala is an actual moment in time. Because of these properties, it can be used to explore the nature of existence, of the universe, and time itself.
When the twins and Nimrod approach Mr. Rakshasas in hopes that he could help them heal Groanin, who had been severely hurt and was trapped in between worlds. His solution was to have them go back in time by using the Shamba-La mandala, in which it would make them go back to a time before any of this had happened. Since Mr. Burton, Moo, and Mr. Swahili were staying, it guaranteed that history would not repeat itself.