I did something similar when I had a scary experience with a few yakuza at an izakaya in a suburb of Tokyo. They were drunk and I was targeted as a foreigner. I simply acted like a lost, clueless foreigner who couldn't speak Japanese. I was patted extremely hard on the back a few times but was able to get out of there. Normally yakuza leave foreigners alone, but I was simply in the wrong place at the wrong time. No Japanese customers came to my aid because they were all scared to death.
