Head upwards and to the left doorway. Inside is a hallway rocket robot; if it is up, duck, if it is down, grapple to the ceiling. Two shots from the Rocket Launcher will destroy it. The red communication room will open the boss door if you Wire-Tap. The silver communication room will tell you that you should use the δ (Blue) transmitter in Area 7 and Area 9. If you Wire-Tap here, you'll receive a message from Joe and then the alarm will sound. The boss room contains two new infantry that carry shields. You can't shoot them, but you can kick them by swinging with your grappling hook.