Note that while one soldier seems to fall quite a long way to his probable death, he turns out to have survived. Just try to initiate the takedown as far away from the ledge as possible with that particular soldier, to avoid any accidental deaths. If he falls like in my video, check his body for the sleep icon afterwards. Lastly, this method is also fine for "Foxiest of Hounds" trophy/achievement - the alarm/Hostile thing doesn't matter in this scene. At least, I'm pretty sure it doesn't, since I got the achievement with the same strategy.
