If you watch though you can see the real forceful push came from the window frame not directly behind the guy in front, but the other one 'behind him' to his left, the "top left" as it were.
Its almost as if the doors are hinged with each other. What looks like happens is the guy on the outside stops the door coming "out" from moving (trying to come in?) and for some reason it causes the top left to swing hard in the direction it was moving and the bottom left doors to swing hard into the guys back at the same time the door in front of him isn't moving.
In other words, In Mother Russia You Don't Open Door, Door Breaks Over Your Face Thank You Citizen.
Russia or not, whoever made the door is a friggin idiot. Every single one of these style doors I've seen they are all connected in one central spot together like spokes on a wheel, not independent.