I watched the news clip on Youtube, here:
First the male interviewee demonstrated the technique, which had him placing the muzzle through the rectangular hole. Then the reporter, Hollie McKay, was recorded showing her shooting with the muzzle behind the hole. Whether she was supposed to repeat the shooting stage with the muzzle placed through the hole or not is unclear. She did a good job at shooting through the hole, a possible alternate method, as she didn't hit any wood.
These step barricades are generally not available to the public but might be used in competition, instruction, or a weapons qualification course.
The step barricades I've used didn't have the "hole" cutout and were used to shoot over or around.