The CORRUPTER cryptonym indicates that a Spartan was infected by the Flood, that safeguards (such as the failsafe charges present in the Gallows VISR upgrade) have failed, and weapons of mass destruction have been authorized for use. Spartans who are not assigned to Flood containment Fireteams are ordered to uphold Emergency Contact Protocol Upsilon, and withdraw to a security perimeter. CORRUPTER further dictates that containment is set as a top priority and allows for an immediate bombardment of the area with Magnetic Accelerator Cannons and fusion warheads.[1][2]

The protocol has been enacted at least once, during an engagement at Site 22 in which UNSC Saturn was forced to turn its weapons on the site of a failed Spartan deployment against the Flood.[3]

Sources