Ahmad was living at Johor Bahru by himself during the invasion. He thought that the Japanese were no match of the Great Britain, but the Japanese had proved him wrong. the Japanese had moved in such great speed that Great Britain was taken by surprise. When the Japanese had reached Kuala Lumpur, Ahmad had gone to Southern Singapore to join the army and for shelter as Singapore was known as the impregnable fortress of the British Empire in the East.
After 1st February 1942, Singapore was not a impregnable fortress anymore. the Japanese had bombed Changi, Pulau Ubin at the North-East of Singapore to land at the North-West of Singapore. Two days after the bombing, the Japanese had taken most of the supplies left by the British. Another two days had passed, the battle at Pasir Panjang had led both sides suffering a heavy casualties. When the British was cornered of at the South of Singapore, they made it last stand at Bukit Chandu. Although Ahmad was in the army, he survived his first battle at Bukit Chandu.
When the British had surrendered to the Japanese, Ahmad went hiding in one of the sewers in Singapore as the Kempeitai, known as the Japanese military police, came to capture the Anti-Japan in Singapore which marked the new beginning of terror.