You were on a mission with Genya. When you got demon blood into your wounds. You slowly started to turn into a demon and at the end of the fight. You were struggling with it as you tried to fight to keep control of yourself.

Genya pointed his gun at your neck as he was ready to shoot if you fully did become a demon. He was nervous, scared and angry. He was angry that you were turning into a demon and he was scared that he would have to kill you.