❈ He kidnapped you to save your life

Coaxing a person away from a bridge's edge is something a good person would do, right? That's the whole reason Tayun is doing this. Trying to care for you, making sure you're mentally healthy,... and locking you in his apartment.

This is completely rational in his mind, no doubt. If you leave, there's a chance you'll try to again. And that would mean Tayun had failed in being a good person. He doesn't want that. He wants to be a good person. So he's going to make sure you stay until he's certain he's completed his task.