Question and questions about Case 15237, the healthcare worker who was on medical leave and went to work for few hours

On 29 April late evening, the Ministry of Health (MOH) announced 690 new confirmed COVID-19 infections, including a 23-year-old female Malaysian national who reportedly has no recent travel history to affected countries or regions.
In its daily update, MOH noted that this case—Case 15237—had reported an onset of symptoms on 23 April, with subsequent tests confirming on 29 April that she has been infected by the coronavirus. The woman is currently warded at the National Centre for Infectious Diseases (NCID), where she is employed.
Given the dire situation, it is curious why the woman’s test results took six days to be confirmed from the onset of her symptoms. Was she not immediately tested after showing symptoms? Given that she is employed at NCID where many COVID-19 patients are warded, was she at high risk of being infected?
Are frontline workers being tested on a daily basis or at least regularly? If not, is that something that MOH will start doing in the near future?
Everyday there are more and more reports from around the world of healthcare professionals being infected by COVID-19. Given the MOH’s recent call for more volunteers to join the SG Healthcare Corps to augment its manpower resources, what precautions are in place to ensure that the health of healthcare professionals are adequately monitored and protected? What of their families?
MOH also said in its update that before being admitted, and added: “Prior to hospital admission, she had mostly been on medical leave and had only gone to work for a few hours”
However, MOH did not specify when exactly was she admitted to the hospital and whether the woman was working while on medical leave.
For now, that’s all the details MOH has released regarding this COVID-19 case in the public health sector. There is no information yet on where the woman might have been infected or if she is linked to any existing cases.
So another question is when did the woman go back to work for a few hours? Also, on what dates did she go back to work after becoming symptomatic?
For cases 2738 and 3014, MOH clearly states that both cases have not gone to work since onset of symptoms. But in the case of 15237, this is not clearly stated out. In fact, it would sound as if the woman had returned to work while on sick leave.
In late March, the Infectious Diseases Act was updated to state that any patient who has been certified as having acute respiratory symptoms by a doctor and given a five-day medical certificate (MC) will have to stay home for the duration of the MC or risk being fined or sent to jail.
The update notes that any person who receives such an MC cannot leave their home or accommodation for five days, the duration of the MC. Those who violate the law could be fined up to S$10,000 or jailed for up to six months or both. The only reason these individuals would be allowed to venture out is to seek medical help.
Additionally, doctors were advised to grant patients with respiratory symptoms five days of medical leave to help curb the transmission of the virus which has resulted in two deaths in Singapore so far. Symptoms include fever, cough, runny nose, and sore throat.
With that in mind, did Case 15237 receive a five-day MC from a doctor? If yes, she was in violation of the IDA. Will action be taken against her for defying her MC by leaving her home to go back to work for a few hours?