He may have suffered a light and temporary heat stroke following the intense battle, which took place on a humid and extremely hot day in early summer, and it is thought that his condition did not raise any questions about his lungs for those close to him, including Kondo and Nagakura.
初夏の蒸し暑い異常な高温下での激しい戦闘によって一時的に軽度の熱中症を起こした等、少なくとも近藤や永倉など周囲の者には肺の方の異常は感じさせない状態であったと考えられている。