What were you thinking?
What were you thinking, on that night you chose to swim all alone?
What were you trying to prove?
What would you have done if he hadn't been there to save you?
The translation and novel is not mine. The author is Takekuni Kitayama and the illustrator is Rui Komatsuzaki. I found this translation in tumblr from Edogawa Translations. So copyrights to them