Swing at his head.
From Create Your Own Story
You rare back with the two by four, grimacing and just waiting to fuck this up somehow, but as soon as his right foot settles down in front of your flashlight, you swing for the fences. You don't mean to, but your close your eyes as you put your whole body into the motion, turning on your heels and putting all of your strength into the blow.
You feel the board connect, and hear a sickening thud, as your eyes peel open slowly and you catch the last moment of impact. Teeth flutter through the night air, and the man's jaw simply buckles under the pressure of the wing, snapping into a weird angle and jutting off his face in a way that's anything but normal. He stumbles, his momentum carrying him three more steps past you, arms flailing, and he collapses face down in the alley. You take another deep breath, preparing to cheer yourself, when you see the muscles of his shoulders tense as he pushes up with his arms to rise.
No chances. Not this time. You move quickly over the man, and swing the wood down on top of his head. You hear the crunch of his skull as it rebounds off the pavement, and as he tries to rise again, you hit him again. Then again. Then once more for good measure. It's hard to see in the backing glow of the flashlight, but the top of his head looks to be oozing blood, and his fingers twitch now instead of pressing against the pavement.
You turn back around, satisfied and feeling a bit lucky, and see the other two men haven't noticed you at all. The woman still screams, and now the two men are pounding and kicking at the door. It seems as if they're actually trying to get in now, and not just terrify the woman behind it.