This area is characterized by low, flat house roofs with small tunnels between them. Use nightvision again to pick out enemies either on rooftops or in tunnels - the latter may catch you unawares. Move through the tunnels (not the road) and head west and north. There'll be a base; hide in the grass and pick people off with a sniper rifle, or alternately move around the edge of the base. Your main concern is the guy in the watchtower on the northern side. If you take out the guard on the west side of the camp, he will probably see it and go investigate - this is your chance to take him out without alerting everyone else. Watch out for reinforcements coming from behind, as well. You can get inside the house by crawling under the gap in the northwest corner, and inside there is a VSS silenced sniper rifle. However, there's guards in the house, and it's more likely that you'll get caught. Head northeast to the Vista mansion.

Shortly after you arrive in this area, the rebels will stage an attack. This area is full of enemies using top-quality weapons like machine guns and grenade launchers, which means both that you should watch out and if you can salvage their gear without being caught you'll make a lot of money. Use strategic sniping to help out the rebels and advance until they get their bulldozer. Defeat the PMCs in the way and it will bust through the door into the mansion. Check the bodies before you head in - look specifically for a grenade launcher, which will be useful later and save you a lot of money instead of having to buy it. Head inside and watch out for PMCs on the roof. Move around the eastern side of the compound. then turn west and head up the stairs. Head to the northern side of the building and roll through the window. Head toward the stairs on the west side - two PMCs will descend. Press against the wall under the stairs and they will pass by. Follow the doors out onto the roof, where there's a heavy machine gun and a mortar if you want to try and help the rebels. Follow the path around and jump in the open sunroof thing, into the tunnel. A room on the right side of the tunnel contains ammo and a ration, which you'll need just ahead. Press forward and climb up the ladder.

After a long talk with Naomi, we get the Laughing Octopus fight. First you'll have to deal with the FROGs - dodge them by luring them to areas, then going around behind them. Use this time to learn the layout of the lab, because you'll be doing a lot of fighting in it. There are only a few areas that only have two ways in - most have three, allowing you to flank your enemies if you're careful. They move in pairs, so use grenades. Be very careful not to get stuck between groups of enemies. Furthermore, this isn't like the fight with Rat Patrol 01 - if you get spotted, it counts as an alert. A good strategy is to just hide under a bed or table pointed at a door, and ambush them as they enter. Use the glass windows as distractions and always aim for the head so they don't have time to turn around and spot you. After the eight FROGs, wander around until Laughing Octopus shows up.

Metal Gear Solid 4 Walkthrough