Graeme was trying to keep his cool as much as possible. He could see that Violet wanted to object to the idea of returning to the dungeon and even to lash out—there was a fury inside of her that he caught with the Veiled, not that he need the Veiled to realize it. She was very visibly enraged. But she knew better than to act out in whatever way she was imagining at the moment.
If Violet were to attack Samuel, himself, or any other member of the pack—including Neoma and Lucas—it would be grounds for much worse than being placed back in the dungeon. And she had no standing in the Thundering Falls pack regardless of the suggestions she had made about becoming their Luna.
