The interior of the Shumulvault is full of traps installed by Bagura and Mujoe, which only they know the locations of. It also contains large numbers of Hige-Hige Bandits, and scientific facilities used by MechaDoc. Furthermore, there is the Bar Touko staffed by the alien bartender Mama, who seems to have her own authority over her small section of the base. Mujoe is a regular patron of the bar during his downtime on the Shumulvault, and is enamored with Mama, who gives him advice and encouragement while remaining disinterested in his advances.
In episode 40, MechaDoc unleashes his plot and takes over the Shumulvault. Later, the Jetters, along with Mujoe, invaded the Shumulvault to try and rescue Bagura. However, they failed. Mechadoc then warps the Shumulvault to a new location inside an artificial black hole (perhaps inspired by the setting of Bomberman 64: The Second Attack!).
It was once again invaded by Mujoe, and Bagura was rescued from Mechadoc, whom escaped the Shumulvault to Planet Jetters.