It would be one thing if she didn't know that Arthur was in danger. She couldn't be blamed for that.
But if she knew that Arthur was in danger, she had to help him. This is her job as a caretaker and there would be no excuse if she did something else instead of helping him.
So far from being able to kill him, she also can't let him die while she is aware of it. This feeling of being constrained gnawed on her mind and made her speed up to get away from Arthur as fast as possible.
Thunder Drake watched her go and shook his head in amusement. Then he returned his attention to watching Arthur.
He too was amazed by what Arthur had done. But he had been desensitized to something like that after watching Sword Flash do it many times.
Sword Flash had also advanced to the fifth mortal coil with his own enlightenment and technique. So he is seeing Arthur do something he had seen before.
