Now time to meet L'Ensemble in Cerebu. While one is tempted to go back to the camp and fast travel to the Safehouse near Cerebu you will arrive 24 mins late using this method. Instead drive to 094-062 and take the boat to the RV. You will arrive with about 25 mins to spare. Use the alarm to advance to 19:59. You will be told that getting to Cerebu is complete and to go to the beach. Get in the boat with men in it. Sail to the waypoint on the shore. Get out, the transport objective will mark as complete and the game will auto-save. Now walk to the silos going steath. Sneak in plant a bomb set a timer just in case. Once the silos are destroyed, that object will mark as complete and the game will auto save. Make your way back to the boat and retrace your route back to Cerebu. On the way back you will get another gurella mission to support an attack. Head to the shore near that point. BUG ALERT! The boat you came in on now only functions as a "crate". You'll have to walk all the to Namuvaka and "borrow" the truck parked there. Men by the campfire will talk about the plan crash and the attack you just did on the supply depot. They don't seem concerned that you are making off with the truck. As it turns out, there is no way to get there in time so that task gets cancelled. I found a boat to swipe at the IDAP depot at 046-055 and went back to the market at 092-059 to buy another explosive charge.
Having received no further instructions I decided to do a lone wolf attack on the Weapons Lab at 024-131 A long boat ride On the way out, the "support attack" task became "live" again (possible bug). It's sort of on the way so I headed there. Land at 040-040. After you kill about for gendarme that objective clears. But another one comes up at a location about 500 meters down the road. That objective never clears, so back to the boat for the Weapons Lab.
As you approach the Weapons Lab, the Doctor calls asking for the counter agent. So you need to get that before you blow up the lab. However it's nowhere to be found. I took all of the other medicine I can find then blew up the tank inside the geodesic dome (once in there, there is only one person to deal with). Once you blow up the tank, Keystone says that he'll be able to get the counteragent and gives you a new RV (the failed radar task gets canceled BTW). Head back to your boat and go to meet Keyston on Sainte-Marine. There you go with him to a sub and that ends the game, as Keyston only had a small sample which needs to be analyzed and duplicated elsewhere.
Another way to play it: After you blow up the silos, take a tanker truck (which is oddly undamaged) and go to 041-056. Snipe the guards, there are only three of them and steal the speedboat HMG. Sail to 016-134 just north of the fence. Get out and go to 049-139 a CSAT armor base. Steal a T140 tank that's there. Drive the tank to the geodesic dome. You have to open the doors first, but don't go in without donning a hazmat suit. Get back in the tank and blow up everthing inside the dome, it will take almost all the rounds, but it will do it. Then take the tank back to where you beached the boat and sail to Georgetown Go to the safehouse at 062-180 and fast travel to the camp. From there get one of your parked cars by the road to take what meds you have to the Doctor. Then retrace your steps back to where you docked the boat. Now meet Keystone at the island. It does not seem to matter that you took a two hour detour.
Final Thoughts: It seems like you can just lone wolf the final objective once you learn the exact location from the recovered photos from the dive mission and not bother with the radar assignment. Maybe not even bother with the sabotage of the CSAT computer network, although the autonomous defenses at the Weapons Lab may give you a real hard time if they had not been disabled.