Upon arrival in Hong Kong, Ross volunteered with the Hong Kong Volunteer Defense Corps (HKVDC). Training included donning a uniform for one weekend a month and an annual 10-day camp during which Ross exercised with two six-inch guns taken from the World War 1 Cruiser, HMS Kent. On 7 December 1941, Ross received orders to report for duty and was assigned as a gunner to 2nd Battery at Bluff Head, Stanley. His wife Rae volunteered as a nurse and served at the Bowen Road Military Hospital. By 19 December, Japanese troops were advancing from the north and 1st Battery, positioned at Cape D'Aguilar were ordered to destroy its guns and evacuate to Stanley Village. Ross had volunteered his car, a Morris 8 to the war effort and under the orders of Captain Douglas Crozier drove munitions and troops (many hanging to the outside of the vehicle) from Cape D'Aguilar to Stanley Village, the position of the last stand of the Battle of Hong Kong. Hong Kong surrendered to Japan on Christmas Day 1941. Ross was originally imprisoned at North Point, then marched to Sham Shui Po Barracks and finally shipped to Innoshima where he worked at Habu Dockyard for Osaka Ironworks. Ross worked on a plate-laying gang for three years before being liberated and shipped to Hearne Bay, Australia. On receiving a telegram from Ross, Rae (who had been imprisoned in Stanley Village) came to Australia and in 1946 the two returned to Hong Kong.