Hostages scream from the hijacked bus at Tanah Merah Ferry Terminal, as the three terrorists menacingly wave their sub-machine guns at them.
But within seconds, the bus is swarmed and surrounded by about 20 men in black from the Singapore Armed Forces' (SAF) Special Operations Task Force and the Singapore Police Force's (SPF) Special Operations Command.
Armed with rifles, hammers and protective armour, the counter-terrorists smash the windows, prop ladders and climb into the bus.
A fierce gunfight ensues and the terrorists are eventually killed or arrested.
The threat is not over.
A bomb in the bus is about to go off.
Personnel from SAF's Chemical, Biological, Radiological and Explosives Defence group are immediately called in.
They diffuse the bomb, but there is no time to rest.
Four other "terrorist attacks" are on - including a ferry hijack, two speedboats trying to approach the Tanah Merah Ferry Terminal, and a bus explosion.
These were the scenarios played out on Wednesday as part of Exercise Highcrest - an inter-agency exercise designed to test the Republic's counter-terrorist capabilities on land and sea.
The exercise, which began on Oct 29, involved more than 1,600 personnel from 20 agencies such as the SAF, Singapore Civil Defence Force, SPF, the Immigration and Checkpoints Authority and Maritime and Port Authority of Singapore (MPA).