The thug in the cap was picked up for possession of a samurai sword in the street - this should have alerted the officer to operate with eagle-eye attention towards the thug. When the thug draws his blade from his waist-band, he has the presence of mind to elbow back into the officer (partly because the officer is lacidasical.) If the thug had been face-on to the officer, its possible that serious injury would have occurred. The thug uses bad attitude of the officer and his own back-turn to momentarily hide the knife withdrawal from his waist band. I would hope that the officer would have noticed it earlier, if it had been a face2face confrontation. Once the officer wakes up, his reactions are reasonably effective before the cavalry ride in to back him up.
