They chased a fleeing boat, accelerating to about 55 knots, or roughly 100kmh, to overtake it.
And when they got close, they had to board the bobbing boat by jumping onto it at high speed.
Such risky manoeuvres are all in a day's work for officers of the Singapore Police Coast Guard (PCG), who, as law enforcers of the sea, stand between Singapore and threats that come across the oceans.
Journalists got a close look at their seaborne operations on Wednesday in the waters near their headquarters in Brani Way.
Amid a heightened terror status, the Coast Guard continues to invest in realistic training and modern equipment to deal with maritime challenges.
PCG head of operations and security Lin Zhenqiang said the officers face a unique set of challenges in their counter-terrorism efforts.
Among them are sea conditions that can change instantly and the types of vessels they may encounter.
The Straits Times understands that vessels of various sizes are sometimes rented to add realism to boarding exercises.
Said Superintendent Lin: "To prepare our officers to adapt to these challenges, we ensure that our officers go through rigorous training in realistic environments."
That means using the Board and Search Trainer, a seven-storey structure at the PCG headquarters which simulates the conditions inside a ship.
Apart from patrolling the seas to deter illegal immigrants from coming ashore, PCG officers also check vessels for contraband and weapons.
On Wednesday, the PCG's Anti-Smuggling Team checked a vessel at random.
While some officers verified the crew's identities, the other officers inspected the ship for potential hiding spaces in the engine room and water compartments.
Back at headquarters, journalists were given a first-hand taste of PCG training.
To nurture confidence, officers practise jumping into the sea from heights, in case they have to abandon ship.
A trial jump from a height of 2m went smoothly, but my heart was pounding as I stood on a platform with an 8m plunge to the water below. The two safety divers in the water looked so small.
Knowing that a poorly executed jump could result in injury, I nervously clutched my life jacket close to my chest and jumped.
It felt like an eternity before I felt the violent rush of water against my face. But other than swallowing seawater, I was fine.
The real test came when I was earmarked, as part of the mock exercise, to be part of the PCG's Emergency Response Team (ERT), which had been "activated" when a ship's captain reported seeing two suspicious men on his vessel.
The team's mission was to clear the ship, ensure the crew's safety and locate the two armed strangers. My mission was to tail the team.
Scaling up the Board and Search Trainer using a 7m-long ladder caused me to sweat profusely, with my bulletproof vest, radio set, helmet and dummy pistol and rifle weighing me down.
But the fitter ERT officers did not seem to have any problem carrying a heavier load of 18kg each.
Trying to keep a cool head while securing every turn inside a poorly ventilated and noisy vessel is not for the faint-hearted, especially with the threat of two armed adversaries.
But the ERT officers returned fire on the "gunmen" and subdued them.
While it had all been a training exercise, I had new-found respect for the highly skilled and courageous men and women of the PCG, who work mostly out of the public eye.