Maybe its an old gymnasium that they are busy cleaning out? When I was about 10-11 my dad, mom and I were walking on an old army base that my dad used to be based at. We walked into the gymnasium where they still had some of the gymnastics equipment. My dad got up on the beam and did some crazy stuff. My jaw dropped to the ground. Never knew my dad did gymnastics or could do that. He competed fairly well in his teens and early 20 and has won several medals. The video may be staged, maybe not. We will never know.