The possibility of having to pay a fine that could be up to 100 billion energy stones or even more than 1 trillion weighed heavily on his mind. But he was still willing to go ahead with killing her because the alternative is to let her go, which is something he finds more abhorrent than a fine of 100 billion energy stones.
She knew too much about him for him to let go. Besides that, he hated her and had always wanted to kill her.
So, as he destroyed the army of skeletons, he also destroyed the Mental World of the rank 5 death cultivator. And he did so without caring about the cost of his actions.
The latter was the first to be completed. In just two minutes of constant attacks, the Mental World was crushed, fragmented, and turned to ashes. This damage also affected the army of skeletons.
