It may not be common knowledge, but hospitals have a variety of colour codes to deal with different emergencies.
This includes the sudden collapse of a patient, a heart attack in a heavily pregnant woman, or even the attempted abduction of a baby.
The codes came to attention last month when Farrer Park Hospital said in a Facebook post that one of its nurses witnessed a car accident just outside the hospital.
As it turned out, the driver had suffered a stroke. The staff nurse, Mr Steve Mocsoy, activated Code Pink - the hospital's standard protocol for emergencies within the vicinity - so that staff on duty would go to the driver's aid.
"We have had close to 10 incidences since we launched Code Pink in March 2016," said a hospital spokesman, adding that most cases were for chest pains - often to do with heart or drug-reaction issues.
The hospital formally opened its door on March 16 last year.
In comparison, many other public and private hospitals use Code Blue when such emergency situations arise.
They are handled by a Code Blue team of doctors and nurses, who are typically on standby round the clock. At the National University Hospital, where Code Blue is used for emergencies on the premises, this team is activated about 10 times a month.
A spokesman for the Singapore General Hospital (SGH), which uses Code Blue in the same circumstances, said: "The first five minutes following a cardiac arrest are the most crucial moments in ensuring the survival of the patient."
He added that in general, emergency incidents outside the SGH campus are handled by the Singapore Civil Defence Force.
Code Red, on the other hand, is used at KK Women's and Children's Hospital to raise the alert when a heavily pregnant woman suffers a cardiac arrest and is not responding to cardiopulmonary resuscitation (CPR).
When the Code Red is sounded, a team trained to resuscitate pregnant women will rush to her side.
And at hospitals under the Parkway Pantai group - such as Gleneagles and Mount Elizabeth - Code Pink is used to alert staff that a baby is being kidnapped.
"Thankfully, we have never needed to activate Code Pink except during our annual hospital drills," said group director of nursing Elaine Ng.
"Our hospitals conduct emergency drills as part of our continuous efforts to maintain our medical team's alertness and competency in dealing with such unusual and challenging situations."