Like fourthrider said, you don't actually kill him in this part, but you will have to fight to survive. Keep your distance from him as much as possible, and when you get the chance, shoot him. If he hurts you to the point where you think you will die, just keep running around and get away from him. There will be times when he grabs you and you will need to press the right button, or continue to shoot him while he is holding you up (shoot him in the face). Just keep it up and you will make it out of there. Good luck.