Start by neutralizing the commander. You can approach him and fire the sleeping pistol, several times, or attack him at a distance (here, you can use the help of Quiet, if only she has an appropriate rifle). After that, sneak up to the captive XO. Make sure that there are no child soldiers around and, if necessary, knock down some of them. Only then, pick up the POW.
The best way to complete this mission quickly is to load the commander and the POW onto the jeep in the village, because you will complete one of the secondary objectives, this way (extracting both targets on the car). The vehicle has been shown in the above screenshot.
After you put both targets into the jeep, do not attempt to fulton it, because the probability of the prisoner's falling out is high. Instead, get behind the wheel and head North. You need to drive the jeep outside of the mission area, thanks to which you complete it.
Note - If, for any reason, you cannot use the jeep, it would be best to request the helicopter pick-up and deliver both of the targets to the extraction area in the Southern part of the map.
Note - After you complete this mission, you learn about a strange illness spreading around the Mother Base. You do not need to perform any actions. Simply learn the preliminary procedures of dispatching personnel to the quarantine zone.