You start this level underwater on your way to a rig off the coast of America. When you surface, swim behind the guard and use your melee attack to kill him your teammate does the same with the other.
Pull yourself out of the water and you're told its suppressed (silenced) weapons only to be used, follow everyone up the stairs and take out the guard. You have to rescue the hostages on the rig and they are held in a few separate locations, the first you are about to reach. When you arrive, there are two entrances you can breach we found the nearest one the best. Plant the charge on the door - when it goes off you will spill into the room and everything is slowed down for a few seconds. Use the slow motion to eliminate all hostiles in the room but make sure you don't kill any hostages! After clearing this room, follow your squad upstairs to another room, again choose to breach the closest door and do the same during the slo-mo by killing the enemies but be careful of the hostages.
When you have eliminated all threats in the second room its time to lay a trap - plant C4 on the body indicated and then follow MacTavish out of the room and up to the vantage point on the platform. You will see a group of soldiers make their way to the room with the C4 in, wait for MacTavish to say to do it" and then detonate the C4, killing some of the guards. Now shoot the remaining guards before dropping down from the platform and moving forward. Take out anyone that comes in front and as usual, use the available cover if you are taking a lot of damage. Eliminate the targets on the stairs and then move up them, there will be quite a few enemies that appear now so get yourself into the building on the right. This provides you with some good cover so use it when needed and kill the guards as they come into sight.
An attack helicopter soon arrives but you are safe while in the building so make sure you have taken care of all the soldiers in there before worrying about the chopper. When you have cleared the soldiers, pick up the rocket launcher that you can find at the top end of the room to blow the helicopter out of the sky - go outside and when you have a target lock-on fire away.
After destroying the chopper push on towards your next marker, again use any available cover when necessary to help you eliminate all threats. You will reach another staircase and you need to head up there and be prepared for a tough section. When you are on the top deck the enemy will have released smoke grenades and they are equipped with thermal scopes - lucky for you there are plenty of weapons lying about next to crates that have thermal scopes equipped so pick one up. Now to pick your spot, we found the best place was to the left there is a squared out section just past a fence that we got settled in. When you are there, you need to peek out from the corner you just came around to take care of the soldiers that are moving to your position. You also need to peek out down the left hand side, a path leads along the edge of the rig and there are guards ahead so you need to deal with them as well. When all guards on your level have been killed you need to take care of the ones at the upper windows situated directly opposite the stairs you came up.
Once all threats have been dealt with, you have one more room full of hostages to breach, we chose the door to the far left to do this. Same thing applies here, when the breach goes off, utilize the slo-mo to kill all of the guards within the room. As well as making sure you dont kill any hostages, you also need to make sure you don't hit any of the explosives in the room. With all hostiles taken care of, follow the rest of your squad as they make their way to the waiting helicopter to get you out of there.
