He escaped to Choshu and was hiding himself in Shimonoseki City, but he was strangled in November of 1864 by the deference faction (Zokuron-to) which came to have the actual power within the domain after the Kinmon Incident.
忠光は長州に逃れて下関市に隠れていたが、禁門の変の後に長州藩の実権を握った恭順派（俗論党）によって元治元年（1864年）11月に絞殺された。