Isaac entered the war in the Balkans on 30th July 1915. He was killed in the afternoon of the 7th August. In his book 'At Sulva Bay', John Hargrave describes Issac's death "It was near here (a deserted Turkish positon towards Kiretch Tepe Sirt) that our first man was killed later in the day. He was looking into one of these bivouacs, and was about to crawl out when a bullet went through his brain. It was a sniper’s shot. We buried him in an old Turkish trench close by, and put a cross made of a wooden bully-beef crate over him."