When you have projection you can open doors and flick switch's but you can also possess the guards. when you get close to them press "A" and you possess the guard, when you do this you can go and kill all the other guards and kill all the camera's. make sure that when your energy gets low to get into a fresh fire fight with the guards and they will take out each other. them wait for energy to return and repeat, this should only leave one guard to kill. if any one know's how to get thru conspiracy and where the security pass is for teh elevator then please let me know.
cheers matt