In 1940, after completing the first year of his PhD studies, Hurst volunteered as a civilian experimental scientist with the Ministry of Supply, undertaking bomb disposal and mine detection duties.  In 1944 he was part of the team, led by John Pilkington Hudson, that defused the first V-1 flying bomb found intact in Britain.  It took the team a week of painstaking work to successfully complete the task, made more difficult by toxic fumes from the explosive and ongoing bombing raids.  As a result, Hurst was awarded the George Medal: his citation noted his "sustained courage when engaged in hazardous operations".
At the end of the war, Hurst saw service in Berlin, assisting with defusing unexploded Allied bombs.