The air exchange valve closed!
The air exchange between room 909 and the outside world slowly came to a stop.
Housekeeper Yao wasn't satisfied with just that and casually opened the negative pressure valve.
What is the negative pressure valve?
This device's purpose is to extract the air from the room, creating a vacuum environment inside.
The original intention of this device was to reduce the suspects' willpower and resistance under mildly hypoxic conditions, leading them to naturally confess.
However, due to the severe threat it poses to life, there's a warning on the device: the negative pressure valve should not be activated for more than three minutes.
If it exceeds three minutes, a large amount of air would be drawn out, and the room would become a negative pressure chamber, turning a person into an ugly corpse, suffocated to death and covered with blood spots and bleeding points!
