This has been completed. Thanks LovansHartes and Taroii. You all held your ground better than me. Tips for other players: Titan Defense Shield and Fusion Rifles all 3 hide behind the rock back left of the level, kill all enemies and don't touch Phogoth until clear then unchain him. Wait like 20 min defending the left side of the map and the Rock. Once Xyor(s) pop out, head back to the entrance Hallway kill the shreeker occasionally. That's all. Sorry but i'm not doing this one again.