Having these reactions just proves that everyone is normal.
A normal person, regardless of personality, will have a natural response to events.
For example, when hearing about these cruel deeds, one would feel sympathy for the deceased, and feel uncomfortable hearing about those gruesome processes.
But the suspect didn't show any discomfort.
He narrated calmly as if those events weren't real, as if he was just telling stories without any emotions, without any fluctuations in mood; it's as if he was talking about someone else's doings, having nothing to do with him at all.
This bone-chilling cold-bloodedness made everyone present shudder.
Kiara witnessed a female compatriot cry during the interrogation.
It was after that man, in a very calm tone, recounted how he hurt an innocent little girl, that the emotionally rich woman couldn't bear it, cried out in sympathy and anger, and broke down emotionally.