I honestly believe that Guwon is an experiment, he has the eyes of the worms/zombies. At the beginning it is said that some were actually hopeful to get immortality, and Guwon crawled out of a collapsed building, so it is likely he's a human experiment with some ADN enhancements of the zombies. And as such, he really has no complete understanding of human behaviour, socialibility, etc, hence why he kills what he perceives to be detrimental to his cause.
DNA*
During the first tutoring session they had, Guwon said he didn't do anything that would lead to addiction, as it may lead to inattention in his duties. So, now... He may become addicted to sex and all hell could break lose. I don't think he has any idea of what consent means, unless he's taught.
Shit, you’re totally right
The eyes changed, does that mean he's in a rut?
nooo, he is in evolution