In a certain sense, this was an extremely sinister and vicious method. If one kept stimulating the Mengling Acupoint with external force like this over a long period, it would easily cause the person's mind to collapse, ending up either utterly deranged, or simply unable to bear it and committing suicide.
As for why the middle-aged man clearly knew this, yet remained indifferent on the side, one had to mention another function of the Mengling Acupoint…
Normally speaking, the term "Heart Demon" only appears in relation to powerful experts with considerable strength; ordinary people find it hard to be associated with these two words. It sounds familiar, yet feels tens of thousands of miles away.
However, in reality, many things that seem distant are actually not as far as people imagine. It's just that they lack the necessary understanding. If you explain it in another way, a different effect will appear.
