i never get found when i do this if you are in/near the room on bottom floor full of boxes and you get detected get a merc 2 face you, use a flashbang to throw him off for a sec, run down the wooden ramp to geto the very bottom floor, and hop into a box, makesure your goggles are off, he wont bother to look inside and will walk off :P works all the time 4 me.