To defeat Ramirez the second time, you must get up and shoot out the lights. He will then only throw grenades. Next, get up close and shoot him to kill him. Shoot out the lights first, but since Ramirez has a powerful gun, run behind one of the containers. If you have a good view, you will see him point his gun away from you. This is your chance to attack. Give him everything you have for a moment, then duck back. First, shoot out the lights. Grenades thrown hard work well sometimes and can possibly take out all four lights at once. Then, run. Remirez throws grenades in intervals of three. Run, then shoot after you are out of the way of the third grenade.