Use your knife.
From Create Your Own Story
"Too much noise," you say, pushing down the barrel and drawing your knife. The old woman moves toward you, dragging one of her legs, apparently more wounded than she looks.
She starts to reach for you, and you panic, having never done this or anything like it before. You slash at her hand with the knife, and lop off her pinkie and dig far enough into her ring finger to leave it hanging. She pulls the hand back quickly and groans as you take a step back.
"Mmmmmm," she growls. "Huuuuuurt me gooooood," she moans, taking another step toward you. You swing again with the knife, almost blinding, and slash her just across the top of her forearm, peeling the skin back there like you were skinning a fruit. She growls again, but keeps coming, so you slash and slash and slash madly, until you've damaged the arm enough that it falls limply at her side.
Claire gets tired of waiting for you to finish the job and steps in with you, reaching up with the butt of the shotgun and smashing the woman in the side of the head. The old woman buckles at the knees and collapses to the floor, a trickle of blood running from the ear just next to the spot Claire walloped her.
"Jesus," she says quietly, looking at you. "Are you trying to get yourself killed?" She points to the woman. "Stab her in the heart or something, we can't just leave her like this."
You take a deep breath, turn the knife over in both your hands, and crouch down by the woman. Has to be done, you tell yourself. Has to. You put the knife just above her chest, close your eyes, and push it down with all your might. The old woman lets out a long slow gasp, her eyes open for a moment, and then she roll back slowly in her head.
You leave the knife and crawl back to put your back against the wall, shocked.
"We have to drag out her. I'm not staying in here with her lying there."
