After relieving miller and his team of the counteragent go back to Dr. Drabek, clear the camp of L'Ensemble. Give him the counteragent, he will then proceed to tell you get off the island using a CSAT SDV at Tavu.
Make sure to bring a Toolkit & Rebreather!
After clearing the camp or sneaking in make sure to use the tool kit to disarm the Naval mine in front of the sdv.
Now all thats left is to avoid the Speed boat patrols and drive the sdv to the edge of the map.