Chen Mu was naked as he kept washing his clothes which were about to turn to rags. To leave no trace of the scent of blood, he kept on scrubbing them to where the clothes that had already been tattered didn't look like clothes anymore. And he still wasn't satisfied, as if he seriously wanted to scrub them into a pulp. Perhaps because of the stimulation from the cold water, Chen Mu had started to recover his strength a little, and his depleted perception was starting to revive.
Chen Mu had kept up his guard while struggling with his clothes and he suddenly seemed to see a dark shadow flash in the water not far away. In the pitch dark of the forest if it weren't for the reflection off the water and the recent enhancement of his facility in the dark, he certainly wouldn't have seen that dark shadow.
He quickly stopped his activity and looked alertly at the creek while almost unconsciously activating the bipolar thunderball card.