5 Chambers by Radical924 (at least a version of this type of map I had on Halo 3). I rebuilt it using the new MCC forge tools in Halo 3. The layout is very similar but built more evenly thanks to the new tools and mechanics on MCC.
This version now includes Silent SMG, Brute Plasma rifle, Automag, Fuel Rod Cannon, Brute Shot, SMGs, & replaced one of the Machine Gun turrets with the badly damaged warthog with it's useable machine gun turret.
Note: this map, while similar to it's original, was built from the ground up in Halo 3 forge on MCC.