This is a street attack which turns into a two on two scenario.  Look for pre-contact cues.  The aggressor shows little “tell” but does encroach and does a very quick load and sucker punch that is more of a upper cut than hay maker.  A good non violent posture would have protected from this and most likely cause a flinch for further protection which could be converted into the S.P.E.A.R.. The attackers energy is committed forward and they are using pretty much straight punches and knees.  The guys being attacked if you notice are trying to push away danger with protective flinches as punches are raining in.  What they don’t do though is engage their attackers.  Meaning, if the natural response is to push away and create space from danger, if you cant flee easily and totally, you must engage.  Space from an attack is only good if its a lot of space.  A little space means you are going to get hit, and most likely hard.  In this scenario the safest place is into the attack, as it gives you a chance to use close quarter tools and jam his big swinging punches. It seems counter intuitive to think the safest place in an attack is forward and close to the attacker.  Whats amazing is that the attackers are putting their whole bodies into their punches and seem to make decent connections but no knockouts, did they break their knuckles trying?  Yes people are walking by and watching and keep on going.  Common in Russia? I don’t know. When thrown off the stairs the one guy taking many blows gets up on his feet seeming relatively fine.  The other is on all fours and not facing his attackers, bad move.  He takes a kick to the ribs that must have done some damage.  He should of faced his attackers and been in a sitting type combat stance, if he could not get to his feet.  The other guy eventually goes to the ground and is on his back, bad move for the streets, as he gets kicked by the friend.  I love BJJ but its not the place for it here. Whether he got to a guard position or even is he was in a dominate position like a mount or knee mount, he would have been open to the attackers friend.