A patient in a wheelchair is seen at a hospital in Seoul, Friday, the fourth day trainee doctors submitted collective resignations to protest a government plan to increase medical school admissions quotas. Yonhap

Concerns are mounting over the potential escalation of nationwide disruptions in medical services as the collective resignations of junior doctors continue, with many of their training contracts set to expire in the coming weeks.

Should the striking doctors choose not to renew their contracts in protest against the government's proposal to increase medical school admissions quotas, hospitals could see a genuine exodus of trainee doctors. This would compound the challenges faced by patients who are already grappling with significant disruptions in health care due to the ongoing walkouts by thousands of doctors.

In Korea, junior doctors undergo training at general hospitals for about five years. Following an initial year as an intern, they participate in a residency program that typically lasts three to four years. Contract renewals commonly take place on a yearly basis, with many set in March.

"Doctors participating in the strike may seek to achieve their resignation goal by opting not to renew their contracts," said attorney Park Ho-gyun who specializes in medical cases.

The resignation letters submitted by doctors have not been officially approved by the hospitals, creating ambiguity regarding the legal liability of their walkout, which comes despite the government's return-to-work orders.

However, if they are no longer officially considered part of the medical staff, following the expiration of their contracts without them being renewed, they are not obligated to comply with the government order.

As of Thursday night, the third day of the strike, 7,863 trainee doctors, accounting for 70 percent of the 94 hospitals nationwide, did not report to work, according to the Ministry of Health and Welfare. They were part of a bigger group of 8,897 doctors who submitted resignation letters. None of their resignations were officially approved, the ministry noted.

The absence of junior doctors, who play an essential role in urgent patient care and operating rooms, has forced hospitals to slash as much as half the number of operations. Medical professionals and fellow doctors have been picking up the slack.

"It is not too late. Please remember that patients are waiting for you at this very moment," said Second Vice Health Minister Park Min-soo during a briefing, Friday, urging striking doctors to return to work.

On the same day, the government raised the health alert level to Serious — the highest level in its four-tier system — from Cautious.

This marks the first time that the health alert situation has been elevated to the highest level due to a medical service disruption, as the protocol is typically implemented in disease-related situations such as the COVID-19 pandemic.