Sector 6 (NOC) is a dark area on the B.S.L research station simulating caves for the purpose of research on nocturnal creatures. Blue X from neighboring ARC can also be found here.
Samus first visits NOC in order to download the data for the Varia Suit. It however is stolen by the Mega Core-X. During a later visit, Samus encounters the Security Robot B.O.X. for the second time.