The Imperial Palace Study Room below houses a vast underground secret chamber, and "Thunder Mountain Residence," which Qin Yu had left for Qin Zheng, is located inside.
Almost the moment True Master Ming Liang abruptly appeared in front of Qin Zheng, Qin Zheng's first reaction was to slap the desk in the study room, and like a man in freefall, he plunged directly into a tunnel beside the desk, whereupon the tunnel sealed itself shut.
As Emperor, it was natural for him to be prepared for assassination attempts, and this passage was created for exactly that purpose.
This slap and fall happened almost simultaneously with Wu Kongxue's low roar. Just as the figure dropped, the ripples of space extended to where Qin Zheng had just been, a narrow escape.