I Admit this was a real though one. There are also a few youtube movies thay might help. You just need to know where to throw the flashbangs. Some say you need to swith to pistol. To be honest that really didnt work for me. I finaly beaten it with only my smg and knife. So i've any has trouble with this too only fucus on where to trow the flashbang and keep you own playstyle.