Thanks for the tips. That boss battle is easy if you opt for killing the skulls - explosives, machine guns and gun emplacements take them down pretty quickly. I'm trying to tranq them because I think you can fulton extract them if you do so. Even with Quiet supporting, their 'tranq' bar goes down so slowly.
Tranq or lethal, the result is the same, they'll lay there in a heap for about 20 seconds and then warp away. You need the maximum upgraded fulton that you get late in the game to fly them out of there. All you get are materials for making particular weapons and camo, btw, they don't join your base or anything.
(Tip for future to avoid heartache: only the last shot counts when you're trying to tranq someone or going for the non-lethal objectives, you can shoot with conventional weapons up until they are on death's door then knock them out with something non-lethal and it will count as such. I learned this the hard way.)
Yeah, I thought I might have wasted my time. The same happened with previous bosses. It is so, so, so much harder when you're tryint to tranquilise them. They have a separate bar for their tranq level and they sometimes re-energise (or whatever you want to call it) which gives them a brighter health bar, and when they're in that state you can't tranquilise them at all; you have to damage them to remove their protective 'shell' first.
I can't wait to go back on tomorrow and blow them to smithereens. The banana splits.
Went on this for half an hour after a break of several months. Think I just got a bit fatigued with it before, but even half an hour was long enough today. Still not even unlocked Africa yet, doubt I ever will.