She gets a bird's eye view of the entire area.

Sergeant Hazel Wong, 23, is stationed in the Tuas Checkpoint operations room.

One glance at the multiple screens surrounding the room shows her the real-time happenings in every nook and cranny of the checkpoint.

She said: "We're mostly looking out for abnormalities or for heavy traffic so we can redeploy manpower to where it's needed most.

"You never know what to expect."

She said she decided to join ICA because she wants to give back to the country that has made her feel "safe and secure" all her life.

Sgt Wong has been with the ICA for more than a year and works a seven-hour morning or a 10-hour night shift.

She said daily challenges range from handling medical emergencies when they have to call in ambulances, to instances where there's a build-up of traffic and they have to redeploy officers to ease the congestion.

"It's exciting. Some days it's a never-ending stream of people," said Sgt Wong.

"You have to trust yourself to gauge where help is needed and you have to think on your feet."