After you kill number XX (Dr. Johansson), look around his operating
room for 2 med kits and about 15 knives. Get your stuff out of his
safe behind the picture in his office as well as the key to the
padded cell, with the nurse. Take the nurse (she is a willing
hostage), and use you throwing knives to kill the guards. Fallow the
halls back to the receptionist's desk and out the door to the
garage, and your finished.
Don't kill any medical staff but security is ok