This is the airlock room leading into the BL3 lab. In this room the scientist take off their lab coats and put on a gown and rubber gloves. After they are suited up, they still have two more doors to pass through before they get to a lab to work with live virus. This lab is kept at negative pressure with respect to the outside space, and all air flows into the lab when the doors are open. This is important to keep the air from escaping with out being properly filtered first.