Hold a direction and just tap 3 times every time he gets near you. I beat him first try.
Finally just did it. 9 times out of 10 I got fucked by the camera angle (can't see shit captain), the other times I would somehow get hit even though I would be 100% fully behind him (hitboxes how do they work). This is really fucking dumb. Probably worth noting I haven't had the slightest problem with the game or dodging in actual combat, it's the crowd + camera angle that makes this minigame specifically really shit -_-.
Edit: Beat katana guy first try. Maybe I'm just weak to men in purple suits? >_>