Ten days before one of Singapore's deadliest terror attacks, 22-year-old infantryman Abdul Samad A. S. Athambava experienced the horrors of Konfrontasi on a deeply personal level.

He lost nine of his platoon mates to Indonesian saboteurs in the jungles of Kota Tinggi, Johor.

The soldiers from Platoon 7, C Company, 2nd Battalion, Singapore Infantry Regiment (2SIR), were taken by surprise, and eight were gunned down on the spot. Another soldier's body was found a few days later.

The dead included Mr Abdul Samad's platoon sergeant, whom he knew only as "Sergeant Ahmad", who had trained him as a recruit for six months three years earlier.

The ambush sparked a search by the entire battalion the next day to hunt down the Indonesian saboteurs.

"It was a shocking event for us, so the whole unit was deployed. We hunted down about 40 Indonesians, although I did not kill anyone myself," said the retired major, now 74.

But Mr Abdul Samad, who was the radio operator for the battalion's commanding officer, and another soldier had to carry four dead Indonesians to their officer's Land Rover to be taken to the battalion headquarters to be photographed and identified.

This traumatic episode was compounded when two saboteurs carried out the bombing at MacDonald House on March 10, 1965.

By that time, Indonesia had been waging Konfrontasi - its low-intensity conflict to oppose the formation of Malaysia - for two years.

The saboteurs chose MacDonald House as it was one of the few prominent buildings in Orchard Road, Mr Abdul Samad said in an interview outside the building, whose main tenants are now CitiBank and international advertising firm McCann Worldgroup.

Two female employees of the Hong Kong and Shanghai Banking Corporation died in the blast, while a male passer-by died in hospital. Thirty-three others were injured.

It was the darkest episode in the three years of confrontation, which saw 37 attacks on Singapore, mostly on soft targets that included public parks, cinemas and telephone booths.

The young infantryman and his platoon were still in the jungle in Kota Tinggi when they heard the news on the radio.

"One of my officers was very worried because his pregnant wife passed by the MacDonald House area in the mid-afternoon every day, at around the time the bombing happened," said Mr Abdul Samad.

To the officer's relief, she appeared in a photograph in The Straits Times the next day, standing outside MacDonald House wearing a white dress and unharmed.

Even after Singapore separated from Malaysia on Aug 9, 1965, Mr Abdul Samad and his fellow soldiers were obliged to complete their tour of duty.

"We were deployed to Tawau, a port town of Sabah, and Sebatik Island. We guarded the borders, to prevent Indonesians from infiltrating. It was not just guard duty as we had to be ready to fight."

For a young man who had joined the army because he needed the work, these experiences were sowing the seeds of change in him.

He said: "It was not anything patriotic about defending the country or anything like that. I joined the army because I needed a stable job. At that time, we were still part of the British colonies with no sense of nationhood.

"But after I saw how we were treated by our neighbours during this period, it made me realise how important it is to build up strong defence capabilities, so we will not be pushed around."

Born in India in 1943, he came to Singapore with his family when he was six. He had eight half-siblings here, and another seven in India. Some of his siblings have died.

He was one of 2SIR's pioneers when he joined at the age of 19 and remembers setting up road blocks during the 1964 race riots to keep the Chinese and Malays apart.

"In those days, there were a lot of strikes, unlawful gatherings, protests and riots. The police couldn't handle it all, so there was a need for the army to move in for crowd control, set up cordons, search and so on."

After his tour of duty in Malaysia, there was no thought about finding another line of work. Instead, he applied to become an officer and was successful on his third attempt, when the Safti Military Institute opened in 1966.

He was one of 300 soldiers selected out of 3,000 who applied, and later became an armour officer.

He got married in 1965. He has four children, who are aged between 43 and 50 now. His youngest child and only son served his national service in the army as a driver.

Having spent more than 31 years in the military, Mr Abdul Samad saw innumerable changes to the Singapore Armed Forces. But he knows there are some things that will never change, for instance, how a small nation needs to always be vigilant to the threats from without as well as from within.

In 2014, 48 years after Konfrontasi ended, Indonesia named a warship after the two MacDonald House saboteurs, Osman Mohamed Ali and Harun Said, who were found guilty and later executed by Singapore on Oct 17, 1968.

"When this issue came back up, it was personal because it brought back bitter memories, but it would have been worse for the families who had relatives who died or were injured in the incidents."

Defence Minister Ng Eng Hen told Parliament in 2014 that Singapore would not allow the frigate KRI Usman Harun to call at its ports and naval bases. The Singapore Armed Forces will also not sail alongside or exercise with the ship.

As a member of the Singapore Armed Forces Veterans' League, Mr Abdul Samad was also involved in a petition to Mr Lawrence Wong, then Minister for Culture, Community and Youth, for a Konfrontasi memorial to be built.

The memorial, at Dhoby Ghaut Green, 100m away from the site of the bombing, was unveiled in March 2015 at a ceremony where Mr Wong was the guest of honour.

These days, on top of being a grandfather to 10, Mr Abdul Samad keeps himself busy under the Commitment to Defence Ambassadors Programme, giving talks to schoolchildren and national servicemen on key chapters of Singapore's history related to defence.

Passing on these lessons that he learnt personally, and often painfully, keeps him going.

"I feel that young people must be told about what happened in the past, otherwise they become complacent and think that nothing can happen in Singapore."

As terror threats evolve, the need to be prepared has become even more urgent, said Mr Abdul Samad.

"In recent years, terror attacks have happened in Brussels, Paris, and Jakarta, using home-made bombs and knives as weapons, carried out by radicalised individuals - we did not have such incidents in the past.

"Especially since we have a multiracial and harmonious society today, all the more we should protect it and not take things for granted."