ArmA 3 Old Man Scenario Part 2 Alternate Ending

Part 2 Alternate (quick) ending.
Now that you know the exact location of the lab just Sail to 016-134 just north of the fence. Watch out for enemy vessels. Best not to hug too close to the target island. Stay outside of the red zone on the map until you are at right angles to the shore where you want to land.
Then get out and go to 049-139 a CSAT armor base. This must be done steath. Steal a T140 tank that's there. Drive the tank to the geodesic dome. Enter the compound by running over the fence, bash the fuel truck out of the way and drive to the back side of the dome.
Park the tank right across from the doors. Get out and 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, unless you aim for the truck in the middle. That will set off a series of explosions that will destroy the facility. SAVE if you have enabled the "save from menu" option.
Now take the tank back to where you beached the boat, but be prepared for attacks from AT soliders and other armor. Sail to lle Sainte-Marine island to meet Keystone. You will get demands from both the doctor and from Syndikat for the counteragent. Ignore them and meet Keystone where indicated on the map.

Keystone will inform you that they only have enough of the countermeasure to analyze and duplicate, there is not enough to give out any doses at this time. Follow keystone to the shore and into the water to a small submersible to successfully end the game.