The woman infected with hepatitis B lost her temper at the doctor.
What she did next underscores the rising incidences of abuse which patients heap on doctors and nurses here.
She pulled out the needle that had been inserted into her arm and threw it at the doctor.
"It was fortunate that the needle did not pierce the doctor, as this could have resulted in her contracting hepatitis B," said Jason Phua of the respiratory and critical care medicine division at the National University Hospital (NUH).
Abuse cases like this one came under the spotlight last Monday when Abdul Aziz Selamat was fined $1,500 for splashing a jug of hot milk at a doctor.
Both NUH and Khoo Teck Puat Hospital (KTPH) say the number of abusive patients is rising.
KTPH said there has been a 50 per cent rise. Last year, there were 33 cases of front-line staff members at the hospital who had been physically abused, an increase from the 22 cases in 2013.
With the number of physical abuse cases on the rise, KTPH is teaching its healthcare staff self-defence.
Started in July 2013, the full-day workshop aims to equip staff with self-defence and disarming skills. This will educate and empower them to recognise, take appropriate action and use simple communication techniques to protect themselves during a conflict with patients or their loved ones.
While NUH did not provide figures, Peter Manning, vice-chairman of its medical board (clinical risk management), described it as an everyday occurrence.
He said people should stop abusing doctors and nurses, who are trying their best to treat the disease or alleviate the pain.
Associate Professor Manning said he has had to step in several times to stop staff members from being harassed.
"The most distressing one for me was one in the accident and emergency (A&E) department.
"A large, heavily-built man was bullying a petite female staff nurse, who was almost in tears. I felt the need to step in between them then."
Prof Manning, who is also an emeritus consultant in emergency medicine, stared down the bully.
There is no single explanation for the higher level of discord, but long waits to see a doctor and a shortage of hospital beds are cited as reasons.
Prof Manning said verbal and physical abuse are risks faced every day by doctors and nurses.
Most of the time, nurses bear the brunt of the abuse, be it from patients or their relatives.
NUH assistant director of nursing Normalis Alwi cited the example of a patient's caregiver who used a pen to point at nurses' foreheads, called them names, took photos and videos to threaten them and even grabbed staff members' name tags.
"He spoke rudely and aggressively, and this made everyone around him tense," she said.
The situation is no different at KTPH, another major hospital that serves many patients.
Staff nurse Leogan Rajh Marimuthu described how he had to intervene when an elderly man, trying to climb out of his bed in the A&E waiting area, argued with a nurse.
Mr Leogan walked over to help and, without warning, the patient slapped him on both cheeks.
"I was shocked. This was the first time I had been slapped, and I was upset for about two days," he said.
Yet, many healthcare staff are loath to take further action against their abusers, saying the patients are sick and often confused by the pain or their condition.
Prof Manning, who has no qualms about taking bullies to task, said: "Unfortunately, this encourages the bullies to do it again and again."
He hoped that, with the Protection from Harassment Act passed last year, doctors and nurses will be better protected from abuse and related anti-social behaviour, and for the hospitals "to be more willing to press charges to send the message that medical workers are not to be abused".
The Act provides both civil and criminal recourse for victims of harassment, alarm or distress, fear, provocation and stalking.
Those found guilty face a fine of up to $5,000, jail of up to a year or both. Repeat offenders face a fine of up to $10,000, jail of up to two years or both.