Having realized that the hidden force behind the "Death of Lycaon" was actually the cyber church...
Russell understood everything.
Why was it that Lycaon, who died from wrist-cutting, ended up with his head missing;
Why, when Lycaon's head was placed in a secret base days later, it showed no signs of decay, as though it had been refrigerated immediately after separation;
Why neither the Three Sages nor the cameras spread across the island could capture what happened in the interim...
Lycaon's body did indeed die from wrist-cutting.
Because living through a "Prosthetic Head" substituting for the real one always involves risks. Moreover, Lycaon did not possess the determination to ensure his survival.
He arranged everything to facilitate his social death, then, in his home's bathtub, he issued a wrist-cutting command to his own body.
After the body's death, Qiao took away the Prosthetic Head—he had indeed returned under the Church's command and could very well do such a thing.