Man gets beat up by nothing on "Part 1, Chapter 2"
You will start out on the bottom floor next to the room with the phone. Go up the stairs through the door to the next floor, then go up the stairs again to the next floor and meet your friend. To your left is a wood pen with a man laying in it. If you shoot the man or throw a grenade in the pen, he will start getting beat up inside of the wooden pen by nothing.