Also the tank is very clearly leaving the square in that video, if you've seen any imagery of the area it's immediately recognizable. (Besides that; it also doesn't make sense that the street is so clear, that close to the square, because the military did encounter serious resistance going in. I wonder why we don't see that imagery floating around 🤔)

He's not standing in the way of them to protest the intervention before it started, he's demanding that the tanks turn around and remain present in the square some time after everything that had occurred.