In Revenge of the Sith, after a wild race through the caves of Utapau, Obi-Wan Kenobi and General Grievous end up on a landing platform further away. At least to me, it appears that the platform is not built by the sinkhole of Pau City, but another smaller one. Is there any reference to what this location is? Is it another Utapauan city or just a secondary sinkhole connected to the capital?
And furthermore, why did Grievous leave the Soulless One there, so far away from the city?
Grievous is famed for having multiple escape plans. It's the reason he's so darned attractive (from a writer's perspective) as a villain.
All the way to Utapau, Obi-Wan considered how best to find and destroy General Grievous. If they blasted their way in, Grievous would only run away again — the droid general was always careful to have an escape ship stashed somewhere close to his command center. He might not even be with his armies. His command center might be hidden in one part of the Utapau system, while his droids massed for an attack somewhere else. - Star Wars: Revenge of the Sith - Official Novelisation
As to where his ship was concealed, the script and novels simply describe it as a "smaller sinkhole" within the city's tunnels. The confrontation takes place on a "small landing pad".
