In Huiyang, Holmes was under the command of Colonel (later Sir) Douglas Clague. He was assigned to deal with external affairs and to co-operate closely with the guerillas of the East River Column (東江縱隊). With the help from the guerillas, Holmes had organised a number of rescue plans trying to save the prisoners of war from the Japanese concentration camps and had conducted espionage in the Japanese-occupied region. According to the recollection of Paui Tsui, Holmes and his companions once secretly entered Hong Kong and reached the foot of Lion Rock. From the foot of the mountain, he used binoculars to spy the concentration camp far away in To Kwa Wan regardless the potential danger of being discovered by the Japanese. Fortunately, although Holmes was a Westerner, the Japanese had never recognised that the fluent Cantonese speaker was in fact a British. Tsui explained the reason was because Holmes was not huge physically and with the disguise of wearing bamboo hat and grey linen clothing, he just looked the same as a common Chinese farmer. His bravery was appreciated by the British government that he was awarded a Military Cross in early 1943 and was made a Member of the Order of the British Empire (MBE) of the Military Division a few months later. It was rare at that time to be decorated twice in a single year.