I believe that after seeing this, everyone will understand what Zhao Hai wants to do. A sheepskin raft. That's right, Zhao Hai wants to be a sheepskin raft.
The thousand feet River was flowing in the same direction as Zhao Hai and the others. This way, Zhao Hai and the others could use the thousand feet River to escape, as the cultivators would not pay attention to the river.
Very few cultivators would go to the thousand feet River because it was too dangerous. It was rare to hear news of evil beasts on the river, but the river was too wide and the current was too fast. If cultivators couldn't fly, it was very dangerous to travel on a boat. Therefore, very few cultivators would go there.
In addition, Zhao Hai and the others were using a sheepskin raft, so they didn't need to cut down a large amount of wood. Therefore, Zhao Hai wasn't worried about being discovered by the cultivators of the divine Secrets sect in the sky.