According to that schematic, the door ahead would lead us into the administrative area. From there we could move into the changing rooms, where people put on the protective suits they needed to wear in the lab proper. Beyond that would be the lab itself, isolated from the outside environment by, at the very least, a double-doored airlock arrangement, but more likely by a kind of autoclave that sterilized everything passing in or out. There'd also be the physical plant that handled support matters such as oxygen supply for the sealed lab.