Tandey was haunted the remainder of his life by his good deed, the simple squeeze of a trigger would have spared the world a catastrophe which cost tens of millions of lives. He was living in Coventry when the Luftwaffe destroyed the city in 1940, sheltered in a doorway as the building he was in crumbled and city burned like a scene from Dante's Inferno.
He was also in London during the Blitz and experienced that atrocity first hand, he told a journalist in 1940, "if only I had known what he would turn out to be. When I saw all the people, woman and children he had killed and wounded I was sorry to God I let him go".
When war erupted the 49 year old tried to rejoin his regiment to see to it that, "he didn't escape a second time", but failed the physical due to wounds received at the Battle of the Somme.
Im’ sure God understood and this is why the battlefield is not supposed to be about mercy. God knew that Tandey didn’t know what Hitler was to become and it’s not like we are supposed to know about these things.