C206 cues

Guo Zhenyu went downstairs to the dorms of the two employees with the intention of giving it a try. He took out the key and wanted to open the door, but there was no corresponding key on the door.

That was true. Since he was already living with a staff member, why would he bring the key with him?

Guo Zhenyu gave it a try and discovered that the door was locked from the inside