Toborro's Palace was a palace built on Makeb by Doctor Oggurobb for Toborro to use as his base. Toborro used his palace as his control center and had a collection Isotope-5 under his throne room just in case the invasion didn't work. However, Oggurobb built a secret passageway that led into Toborro's throne room without Toborro knowing about it.
The Jedi found an went through the passageway to defeat Toborro. Toborro set the detenator for the isotope-5 and the Jedi then left to let Toborro meet his doom.