You will begin this mission creeping through the dark ruins of lower Dubai. Lugo will tend to Adams' leg injury without the use of morphine, ensuring that he will be able to continue following your orders without getting a cloudy head. Walker will tell his squad that you will have to throw your lot in with a CIA agent named Gould, the one whose orders saved your life in the last battle. As Adams blasts through the double doors ahead, you will regain control of the action.
You will find yourself in the lobby of a nice hotel. Gould will radio you and fill you in on the situation. Unfortunately, an enemy helo will interrupt him and, as you walk into the lobby with the two giraffe statues, enemies will begin to fire upon you from above. Shoot the windows out from above to send the enemies falling down into the lobby. After this brief burst of action, take out whichever of your guns has more ammo and shoot the large windows on the opposite side of the room repeatedly to send a torrent of sand pouring into the room, creating a makeshift ramp to the next area. When you walk outside, you will see Gould and the rest of the CIA agents doing battle with the 33rd. A helicopter will get shot and spiral off into a nearby building, creating a large smokescreen between you and Gould.
Proceed to the right side of the highway and rappel down to the lower level using the ropes at the front of the highway. Follow the graffiti on the walls back towards the blue billboard. Loop around to the left of the billboard and you will come across a gruesome scene as bodies hang from all of the light posts in the street. You will have to do battle with a group of enemies ahead, but they don't know that you're here yet, giving you an opportunity to start things stealthily. Use cover to proceed safely towards the vehicles ahead, and order your squad to equip silencers. Have your squad kill the enemy in the vehicle as you drop the enemy to the left of the vehicle. If you start a firefight, you will have to face many more enemies, who will come in from both the left and the right walls of the area. It's best to get through silently. Even if you do manage to sneak past the initial enemies, more enemies will await you slightly farther down the highway. Use the cars for cover and pick off the enemies as they rappel down from the ruined highway. If you get into a tough spot, remember that you can toss out a frag grenade into the sand to create a makeshift smokescreen.
Although this spot will be thick with enemies, you should be able to pass through easily enough by utilizing the cars for cover and by tossing out plenty of grenades. When you have advanced far enough, take cover inside of the bus and shoot the two enemies on the other side before vaulting through the broken window. Head past the cover to find an ammo box next to the makeshift caltrops. Refill your ammo and keep going. More enemies will await you in this next area, although there will only be a few. Shoot past the sand bags to kill the few remaining enemies and then follow the flooded-out highway up to its next destination. Drop down to the next level, which will be filled with rotting corpses. As you proceed towards the stairs, a blast of white phosphorus will fry the people ahead of you. Proceed through the flaming wasteland, avoiding the corpses on the ground, and take cover behind the three rectangular barriers ahead.
This will be your first encounter with a heavy soldier. These formidable foes wear heavy body armor and weild light machine guns. It will take a lot of effort and precision to kill these enemies. Shoot the two enemies flanking the heavy soldier first, and then order your squad to focus their first on the heavy. Aim for the tiny faceplate in his mast to break the glass and send bullets flying through into his face. When he falls, proceed into the building ahead and climb up the ramp of sand to finally reach Gould. As you reach him, you will find that he is already in enemy hands.
Walker and his squad will take cover on a balcony overlooking Gould, who will be getting interrogated by several members of the 33rd. Lugo will tell you that he has a clean shot on the enemies who are interrogating Gould, along with a poor civilian woman. The problem is that there is a large group of civilians being held by the 33rd here as well, and they may not make it out if you try to save Gould. Adams will beg you to save the civilians, while Adams will tell you to take the shot on Gould's captors. This will be the first instance in which you will have to make a moral choice in order to further your mission. When gameplay returns to your control, take a second to think about whether you'd rather save Gould, or the civilians. If you want to save Gould, simply open fire on the three soldiers around him. If you want to save the civilians, head over to Adams and open fire on the enemies with the civilians.
Either way, you will initiate a large firefight. Jump down to the lower level and take cover behind the square planter by the highway posts. You will be able to see the enemies congregating by the sandbags from here. Shoot the enemies near the sandbags, and then rush to take cover behind them. More enemies will be pouring in from over the tall wall on the opposite side of the battlefield. If you need more grenades, take a second to loot some from the box to the right of the sandbags before firing upon the enemies congregating on you. A shotgunner will enter the field, so be sure to kill him first.
When the fight is over. refill your ammo from behind the statue of the horse before heading back over to meet up with Adams and Lugo. Whichever choice you made, you will have to face the consequences. Either way, you will find Gould's operation plan. This will give you the incentive to move forward to the next area and reason to continue your mission. Run past the horse statue and search the sandbags by the basketball court to the left to find the path ahead. As you open the door ahead, your squad will fall apart and start fighting. Walker will have to calm them down, which will lead into the next mission.