Cave 8 is one of the 13 caves that make up the Toha Heavy Industries complex. Mensab is the AI that is responsible for the security in this cave. The cave is locked in quarantine, just as all other caves, due to the Silicon Life infiltration into the complex.
Killy, Cibo and the Electrofishers first get into Toha Heavy Industries through one of cave 8's hatches. Mensab then teleport all the Electrofishers to cave 13.