Milton Douglas Sinasac grew up in Windsor, Ontario. He was a structural steel worker and machinist before the war and had served four years in Essex Scottish Regiment. He enlisted in Windsor on 15 September 1939 and was assigned to the 11th Field Company, Royal Canadian Engineers. He likely trained in Petawawa before being sent to England.
During the preparation for Operation RUTTER and subsequently Operation JUBILEE, Lance Corporal Sinasac was selected to take part in the special unit being assembled around the 7th Field Company to support the Raid. He landed as part of Lt Bill Ewener's Demolition Party on WHITE BEACH. When it proved impossible to get to the demolition targets using their planned route, Lt Ewener led his party towards the Casino with the aim of passing through and approaching the targets from there.
The fight to the Casino was costly and many sappers were killed or wounded and much of their demolition stores lost, but get to the Casino, they did.
By this point, Lt Ewener was too wounded to carry on and L/Cpl Sinasac stepped in quickly. With two other sappers, they took the charges Ewener had been hauling and started on their way toward the massive roadblock on Rue de Sygogne to open the way south into town. Their charges were insufficient so Sinasac went back to the Casino for more, the other two in his party being wounded. With a third sapper from the Casino, he collected what heavy charges could be found and returned to the roadblock. On the way, Sinasac was hit by a burst of machine gun fire and knocked to the ground. The explosives did not detonate, but he received a bad hand wound and was pinned down for over ten minutes. When they managed to get to the roadblock, they placed what they had and fired the lot.
A member of Lieutenant Ewener's party, Lance-Corporal Sinasac proceeded with his Commanding Officer as far as the Casino during the action at Dieppe, 19 August 1942. When Lieutenant Ewener, due to wounds, was unable to carry on he led the demolition party of six men from the south door of the Casino across the machine gun-swept esplanade towards the Rue Dusqesne road block. Fire was so heavy he could not reach this objective but managed with two other men to attain the Rue Syngoyne road block where he left the men while he dashed back to the Casino to bring up more wall charges. In returning he was wounded but with the assistance of Sapper Laur carried back two more charges through the enemy fire. At the road block he fired the charges but due to the heavy machine gun fire had to withdraw his party and was not able to observe the extent of the damage. He was again wounded but managed to return with his group to the Casino. While being evacuated his Landing Craft assault was sunk but Lance-Corporal Sinasac was able to swim to a nearby craft. Throughout the operation this Non-Commissioned Officer showed exceptional personal bravery and determination.