Gears of War Act 2 - Dark Labyrinth
After cut scene enter the room ahead and exit through the door on the right. Follow hall until Marcus can go left. Then go through door to left. Walk up to the door and kick it open.
When Marcus goes through the door, three wretches attack. Dispose of them. Follow the hallway to the right. Enter the door on the right when you get to it. Cross the room and chainsaw the dresser.
Go through the door to the next room. There is a door to the left. There will be like 5 wretches that come from that direction. Kill the wretches and then go through the door. Follow the hallway to a door on the right.
Go through the door and continue straight in to the next room. Take the door to the left. There is a propane tank in a pushable car. Shoot the tank and run after the car as it rolls down the street.