Call out to the man to stop.
From Create Your Own Story
"Hey!" You shout. "What the fuck are you doing!? Stop!"
The man steps over the woman, then turns his head to look at you. She lies on the floor, writhing and crying, and he takes another step in your direction. You can see now that the knife is covered in blood, and there's a smattering of it across his forearm and splattered over his shirt. As he takes another step, a beam of moonlight shines across his face, and you can see large pustules across the bridge of his nose and across his cheeks. He's smiling ear to ear, and the expression in his eyes sends a chill up your backbone.
"Don't come in closer!" You shout, trying to sort out your next move.