Kyouichi Nirasaki heads new medicine development at Nishibashi Pharmaceuticals. When laboratory technician Nobuo Tanaka accidentally ingests an experimental pill, triggering biological contamination, Nirasaki seizes control via emergency comms. He directs Tanaka to collect all related research data and drug samples from the Yamanashi lab for immediate delivery to Tokyo headquarters, stressing absolute secrecy to prevent authorities from becoming involved.

As the crisis intensifies, Nirasaki attends critical meetings with Nishibashi's president and Japanese military officials. He reveals the ingested drug originated from a classified contract with the Japan Self-Defense Forces, designed to counteract biological weapons. Nirasaki identifies Tanaka as the source of lethal gas emissions, caused by an unintended interaction between the experimental drug and Tanaka's flu medication. During subsequent strategy sessions with military and U.S. counterparts, Nirasaki backs efforts to neutralize Tanaka, prioritizing disaster containment above ethical concerns or transparency. His actions underscore themes of corporate-military collusion and bureaucratic crisis mishandling.