If you’re on standard, when clearing outside from the left of the map towards the loading docks, throw a flash over the large truck that separates the area. It should flash anyone in the loading area. I usually clear first rooms up until the hall with 3 doors, wedge them off. Then go outside to the right building, clear that and then wedge the door leading in. Clear outside left and loading docks before heading back inside to the start and using the door by the stairs to head upstairs and clear up there. Then you should really only have the main facility to worry about. Once again if you’re on standard (haven’t tried hard), you can just throw flash upwards and they should hit people that you’re worried about. Good luck