Li Xu had once come across a very interesting experiment report.
The contents were: In Europe, a bored out of their mind laboratory secretly selected a test subject, then staged an extremely realistic scenario.
The scenario was, a long-planned kidnapping, followed by torture.
The test subject was taken to the experiment site completely unprepared and then saw "kidnappers" brutally physically destroying and tormenting a man.
Partway through, a small stove was brought in, and a glowing red-hot coin was taken out of it.
In the dim environment, the brightness and heat of the coin could be clearly felt from close up. The test subject was terrified and had no idea that this was actually just a well-orchestrated act designed to make him believe without any doubt.