Source: “Duty Nobly Done” relates on page 223 that Private Walker assisted in repelling a German trench raid on March 13, 1917 in the Vimy Sector.

Death Followed Decoration
Five days before he fell in action Pte. Reginald Henry Walker was awarded the Military Medal for gallantry. The Star broke the news of his death to his friends in Toronto. “Is he killed? The poor fellow; he was a good honest boy.” Thus did Mrs. Margaret Nolan, 51 1/2 Mutual street, speak of him when she was informed that he had been killed in action. “He promised to write, but we never heard from him,” added Mrs. Nolan.
“Tommy Evans enlisted and Jack decided to go with,” Pte. Walker’s widow and child live in England. Prior to enlistment he worked at the Massey-Harris works. He was 38 years old and went overseas August last.
Source: Toronto Star – May 2nd, 1917.