So John did that to June because he is shattering mentally, he is angry at himself, guilty with himself, sad with himself, all the things, he is angry because he couldn't realize he had angered night by leaving for hebra, guilty he couldn't save their relationship, sad for the same reasons, now that the adrenaline of him doing that to June is over, he is even more guilty
yes, a complicated character, kinda hoping for a villain arc but nyd might do something to prevent that, I like complex characters