Why didn't Veraxitoc kill Shamgar? He still could if he wanted to. But, it wasn't in hi, to just kill.
"It's not in my nature to kill where one can scold. If she was my daughter, or my partner, then I would be angrier, but she is not family of mine. I have no responsibility for her, and can only advise her, and tell her off like any other Elder Dragon would." He was being truthful in itself, and he didn't lie. But in his head, Veraxitoc wanted to see just how far the couple would go to be together. The experiment, in Veraxitoc's eyes, was still on going. If the couple kept meeting at night, despite his warnings, he would leave them be. He wouldn't tell them that, but he would not hurt them. They were his experiment, his guinea pigs in a cage.
Seh'lvah got up, finally find the strength to move. She looked at her bite wounds, and then decided to lick straight across them. She hadn't expected it to be quite that painful. She howled as she licked the wound, falling on her side in pain. Now she just wanted a cuddle. She hurt a lot more than she expected, the adrenaline wearing off, leaving her in agony.