In their memories, if the walls were made of mud, then no matter what, they couldn't be watered.
Even after the walls dried, they couldn't be watered, because under the erosion of water, the dry mud would become soft again, or even fall apart, which was something that would absolutely happen.
In the eyes of everyone, although this gray-black material is now incredibly solid, they imagine it must be as afraid of water as mud is, and a rush of water might wash it away.
However, at this moment, Lin Yi had already given the order and instructed them. Therefore, no matter how confused or puzzled they were, they had to toughen up and do it.
So, they could only nod to Lin Yi, indicating that they understood and remembered the matter.
Seeing this, Lin Yi also nodded in satisfaction. He seemed to notice what these people were thinking and understood their doubts.
