There is a wall built around the Sanitiser Unit, which separates the virus room from the non-virus room. This wall contains absolutely no air gaps.
The trays must go under water in the Sanitiser Unit to get from one room to the next. If the water level falls below a certain level, an automatic door slams shut sealing all air gaps and shutting the system down. During the CIP cycle, the sanitiser door will automatically close, assuring that no air will ever pass through rooms.
