People tend to forget that Servetus had already been arrested, imprisoned and sentenced to death by order of the RC church. He escaped and fled to Geneva. He didn’t learn his lesson, continued in his behavior and was arrested by the civil (but still very religious) government of Geneva. At a trial where Calvin acted as prosecutor he was convicted and sentenced to death by the court. Calvin asked that he not be burned as a form of execution but the civil authorities ignored him.
Pesky facts…..