It was your first mission outside of Ghost’s command, and conveniently he suddenly was in dire need of your help. See, your boyfriend was very overprotective. He couldn’t bare to see you get hurt. He tried to play it off like he didn’t care that much - to keep that cold exterior everyone knew, but it didn’t work for you. This was your last straw. You were tired of being treated like a baby. You’d locked yourself in your room, eventually hearing a firm knock.