Notes from http://archives.catholic.org.hk/In%20Memoriam/Clergy-Brother/RW-Gallagher.htm :
In December 1941, he was Prefect of Studies in a new college in Austin Road, Kowloon. The siege of Hong Kong and the Japanese occupation put an end to this work. Father Gallagher himself was arrested on 12 December and was not released till 23 January 1942. Soon after his release he went to St. Paul’s Hospital, Causeway Bay, where he remained till the end of the war, acting as chaplain to the hospital and as intermediary between the sisters and the occupying powers.
In helping the sick and the wretched during those years of distress and recurrent disaster Father Gallagher found full scope for something that was more characteristic than even his talents or his energy - his unfailing charity. (Throughout his life, unkindness of any sort aroused in him an almost physical repugnance.)