The dark room where Cheng Daqi and his companions waited was the central air conditioning ventilation room of the library.
This place housed numerous central air conditioning units, including many ventilation ducts.
All the ducts led to the roof, and between the ventilation room and the roof was a protrusion about 1.5 meters high, resembling a small house.
This was the part where the ventilation room was higher than the other rooms, and there was a door on one side of the small house, but it could only be opened from the outside.
Generally, when maintenance was needed for the central air conditioning ventilation system, the maintenance workers would climb the stairs from outside the library to the rooftop, and then open this little maintenance door from the outside.
Through this door, one could enter the ventilation room.
Nina had the key to this door, but they couldn't open it from inside. The arrival of the female reporter was like a gift from heaven.
