They respect each other. Nobody is stealing each other's fish. While some appear worried, most affect a nonchalant attitude. In Japan, where manners are still so formal that people bow when presenting business cards to each other, emotion is not something to be worn on the sleeve, or on the face. The auction is not a long, drawn-out process as at Sotheby's.
Bids are simultaneous.
This is fresh fish, and it needs to move fast. A fish is sold every few seconds. Some bidders, disappointed to have lost to a competitor, scramble quickly to go to another auction in the few minutes that remain before it, too, ends. Some of the bluefin that failed to sell at the standing auction may be sold this way. All of it, however, will sell, and quickly.