Complex sentence: The prison guard eventually arrived and Ressler left unharmed, with Kemper displaying no physical aggression and stating afterwards that he was joking, but Ressler never entered a cell alone again with Kemper.
Split into simpler sentences: The prison guard eventually arrived and Ressler was unharmed, with Kemper displaying no physical aggression. Kemper stated afterwards that he was joking, but Ressler never entered a cell alone again with Kemper.