The most heartbreaking episode features Investigator Mika, who spent three years in a cult. She never broke character. She married the cult leader (by mission order), bore his child (by mission order), and witnessed his arrest. After extraction, she sat in a normal coffee shop, stared at a latte, and whispered to her handler: "I don't know how to order coffee as myself. I forgot. What do I like?" She succeeded. But she was no longer human.
The enemy expects human weakness: hunger, loneliness, sexual desire, greed. To counter this, the perfect investigator must become a social chameleon to a pathological degree. In one famous training scene, a veteran says: "You are not a person. You are a camera with legs. You record. You report. You do not feel the cold. You do not enjoy the wine. If you laugh at the boss's joke, you are not laughing because it's funny. You are laughing because the mission requires a laugh at 19:03:22." Secret Mission - Sennyuu Sousakan wa Zettai ni ...
Consider Arc 3 of the series, where Agent Kaito infiltrates a yakuza-owned construction firm. He goes by "Takeshi Suzuki" for 11 months. He eats like Takeshi, laughs like Takeshi, and even develops Takeshi's habit of scratching his left ear when nervous. One night, while alone, he looks in the mirror and cannot remember his birth name. He whispers, "I am Kaito… right?" That moment of hesitation is caught by a voice-activated lie detector hidden in his apartment. After extraction, she sat in a normal coffee
Ongoing. Your move, Agent.