I think the turtle felt lonely and that's why she didn't let him go, she felt she finally had a friend

Well—friend...maybe she wanted a friend, or maybe a more special one hehehe, anyway, you really need to watch it to find out! It was really weird and unusual for me to watch a dialogue-free movie, but eventually I somehow got used to it as the movie progressed.

The loneliness of the man really affected me; even though there are no words spoken, his facial expressions and body movements were enough to convey the loneliness he felt on that island. Even though I'm an introvert, I don't want to experience that all-alone-in-an-island experience.

By the way thanks for the compliment @elbuhito. I really appreciate it (⁠⸝⁠⸝⁠⸝⁠´⁠꒳⁠`⁠⸝⁠⸝⁠⸝⁠)!

Good day!