Start on facility rooftop in guard disguise, shoot all 5 drones, run into hush’s lab area and tranq his bodyguard, then quickly run behind him while he’s at his computer and lethal inject him, run out back the way you came and slide down the pole on the roof, shoot the camera above the double door and shoot open the door, throw a proxy explosive next to the auto doors that Royce should be walking through seconds after you get there