Solution.

Shi Lang was not joking when he threatened the man in front of him. Watching the man not reacting he picked up a knife and walked forward, then he stabbed the knife right above the temple of the man. The warehouse echoed with a loud scream. The supraorbital nerve transmitted a highly painful sensation in the man's brain. 

The knife was left stuck in the temple and Shi Lang had no expression on his face after all this. The four operatives that Darcx had called over shivered when they heard the voice. Shi Lang then picked up a clipping tool from the side table and clipped the other Supraorbital Nerve with it. 

The man cried louder, and Shi Lang tilted the chair backward slightly and opened a tap on the container slightly. He said, "I hope you can hold on for six hours. Do not worry, I have all the time in the world." 

A drop of water fell from the tap and landed on the man's forehead. Darcx asked, "Boss, what will this drop of water do?"