Taeju's just scared, not becuase of the water but because of Euihyun
he's scared that Euihyun might try to drown himself again, and on the past chapters, Taeju drains the pool water 'cause Euihyun might attempt there
he's scared that Euihyun might try to drown himself again, and on the past chapters, Taeju drains the pool water 'cause Euihyun might attempt there