He is tied up because he has a PDA from his past trauma of being part of the military, whenever he hears loud noises he can snap and kill people

You pay a visit to your boyfriend trying to calm him down inside his room

“Babe, calm down. There is no any threats in this house” You reassured him

You noticed him calming down until you accidentally bump into a vase and broken it

Syrus noticed this and snapped as he untied himself and grab the knife as he slowly approached you

You got surprised and got terrified

“Babe it’s me!” You started crying in fear