Duncan entered the war in the Balkans on 31st July 1917. He is mentioned in a list of men who went with Lt Smith and a party of stretcher-bearers to collect wounded between Green Knoll and The Pimple, Suvla on 17th August 1915. He was originally listed as missing but was later determined to have been killed that day around Jefferson's Post area.
In his book ‘At Suvla Bay’, John Hargrave’s describes the disappearance of the party and makes a reference to Duncan Bell:- “Early that morning they had formed up, and gone off under Lieutenant S--- along the mule track overlooking the Gulf of Saros. That was all. There was still hope, of course...but there wasn't a sign of them to be seen. The machine gun section had seen them pass right along. Some officers had warned them not to go up, but they went and they never came back. There were rumours that one of the N.C.O.'s of the party, a sergeant, had been seen lying on some rocks. `Just riddled with bullets---riddled!'.... It made the men heavy and sad-minded...... `Ah!---an' Bell, Sergeant Bell...riddled they say...some one seen 'm, artillery or someone!' It hung over them like a cloud. The men talked of nothing else.” Three of the men did return - two at first:- “I shall never forget those two little figures coming into camp. They were both trembling like aspen leaves..... When they were questioned they could give very little information..... ‘What about the sergeant (Sergeant Bell)?' ‘We got cut off...cut off...we tried to crawl away at night by rolling over and over down the hill, and creeping round bushes...always creeping an' crawling...but it took us two days and two nights to get away...crawling, creeping and crawling...an' they kep' firing at us...'”