The person in rigidity is not in mental peace. His restlessness is just not visible. His pulse, his blood pressure, his body chemistry. He is almost soulless. Lonely and in deepest suffering.
The cold-blooded man has soul knowledge. That is why he can act without fear of death. If he is conscious of knowledge, then he is a saint on the mountain, resting in the soulish, or perhaps he is a craftsman devoted to God, working powerfully to further life.
The cold-blooded one, who is fearless and does not know why, uses his fearlessness as a weapon for material purposes, for the attainment of power and wealth. Deep inside he understands the world. Outwardly, he is its slave. He is a dangerous man, for the world is nothing to him.