You do sadly have to knock out pretty many here, but it's easy to do atleast. The last part sucks. I wasted very much ammo there, as I just wanted it to be over. You can try prenatual's method, but once they get you, you might very soon need to use a medpack. You gotta choose to not use medpacks, or to shoot them. If the game had quicksave I'd spend more time trying tactics, but that takes time with checkpoints, so fuck it.