Battle of the Quarantine Zone

Background info
The Flood have escaped because the Arbiter turned off the Containment field, so the sentinels are attemping to kill the flood. Miranda moves in with a load of marines to secure the Index, but are met by flood who halt their progress. By now the arbiter has met up with Halfjaw,and they go to secure the Index as well. The flood and sentinels fight it out and the arbiter and the humans tussle for the Index.Arbiter wins, only to be blown of the edge by Tartarus.