In the final shot, the actor playing the sensei who judges Michael and Dwight's fight can be seen breaking character and struggling to hide laughter.
When everyone gets off the elevator after the fight, Rainn Wilson struggles not to smile after running into the door.
The candle Kevin uses in the cold opening as he exits the bathroom stall is the same ceremony candle used in the episode Office Olympics
When Dwight calls his sensei, Ira, he gets cut off before saying "Arigato Goazai Mashta", which is an incorrect pronunciation. The correct form for what he is meaning to say is "Arigatou gozaimashita", which is a thanks to something that has been done to you. For instance, you could say it to a teacher after a lesson. Along with "Sempai", which should be "Senpai" and Michael falsely identifying a Kanji as "California Roll", these are just a few of the moments satirizing Dwight and Michael's "fighting knowledge".