Additionally, on the topic of Gamzee, Gamzee was always violent when he was sober as revealed in a doomed timeline that an Aradiabot got the First Guardian code from. Gamzee from that timeline murdered everyone but her while in game. Since Gamzee was a part of Lord English, this may have hastened his turning on the group. He did say that he had realize the Messiahs were always him and him. Maybe he meant literally himself and the part of him thats in Lord English.