What Nil was doing might indeed look like torture. But it wasn't as extensive as the buffalo thought. He was just executing the idea he thought would have the highest chance of success when it came to killing the buffalo.
The idea he had come up with was a little convoluted, but it wasn't as extensive and costly as the buffalo thought. Because unlike what the buffalo was experiencing, the maze wasn't that large, and it didn't take Nil too much mana to maintain it since he could recycle the mana in the broken walls and the walls that the buffalo thought it moved past.
Nil had originally intended to create a maze on top of the entirety of the metal sheet so that he could keep the buffalo occupied while preparing what would actually lead to the buffalo's death.
But when the buffalo decided to burst through every door instead of following the impossible maze, Nil realized that he didn't need to maintain the entire construct as long as he played his cards right.
