Yan Fei was well aware that the incident involving Haruji Harada was merely Japan's attempt to probe Dream Island after receiving intelligence about his mysterious disappearance. Although the lieutenant colonel had severely injured him, she could not be certain that she had actually killed Yan Fei. Therefore, Japan utilized a previous plan to test Dream Island to see if Yan Fei could swiftly respond.
Other forces were merely observing the situation with detachment, ready to adjust their own plans based on Dream Island's response to the incident in order to maximize their benefits. If they noticed that Dream Island couldn't quickly handle Japan's provocation, or if Yan Fei didn't appear at all, then the situation for Dream Island would become extremely dangerous.
