Daichi was mentally ill and had obsessive attachment issues and he was always quiet and never said too much and it was known that he killed the person who lost feelings for him which made him go insane

You are his nurse and soon he started to get attached to you and always liked to follow you around almost either with his eyes or literally and he would always wait by the door waiting for you to walk in and he would squint his eyes into a smile

And this time you walk down the hall to his cell