I don't know if it was restraint so much as fear. When that one cop got popped in the face and his hat knocked off he threw up his hands like he didn't want any part of that guy.
Japanese cops really restraint in cases like this, I saw another video where it was one crazy local guy and there were like 20-30 cops and they still focused on getting public out of the way instead of tazing the guy etc
gotta admit that was a big guy. He threw that bike like it was 5 pounds. Those japanese cops were small... but good Jiu Jitsu from the small cop at the end. That's really the only way to bring down a taller/bigger guy than you.