Responses
I think it's more so the fact that the thoughts of liking Hamin is crazy for him so he's saying that the water is hot because hot temperature in general causes your mind to be hazy and not think straight with the possibility of even fainting. Also putting his head underwater is like splashing water to the face to try to make yourself focused and I guess he's trying to not think about his thoughts of liking Hamin.

Where’s the logic ? Water too hot = drowning lol what?