Doctor X: Mafia in White, released on October 9, 2026, is still airing. However, the episodes so far have given Gye Soo-sung enough reasons to expose fellow surgeon Na Dae-il, played by Jang Seung-jo.
Episode 4 ended with Soo-jung discovering initials engraved on a patient's liver during surgery. It linked Na Dae-il to a surgery performed 15 years earlier.
Doctor X Mafia In White: Will Kim Ji-won Expose Na Dae-il’s Secret?
SBS released a preview of the upcoming episodes of Doctor X. The preview showed a confrontation between Soo-jung and Dae-il.
Jang Seung-jo have crossed a line that goes far beyond professional arrogance.
What Is Na Dae-il Hiding?
In the latest Episode 3, a major revelation came through Kwon Choong-hyun, a pharmaceutical company employee. Fifteen years ago, Dae-il operated on Choong-hyun when he suffered internal bleeding after being beaten by senior officials.
Dae-il not only saved Choong-hyun’s life but also testified against those who were responsible.
In the present, Kwon’s deteriorating health condition exposes a different side of the surgeon. While the medical team was recommending urgent surgery, Dae-il was adamant about giving Choong-hyun's case to another doctor.
After looking at the scans of Choong-hyun, Gye Soo-sung confronted Dae-il. Dae-il suggested that the abnormality on Kwon's liver was probably scar tissue from the earlier surgery.
But Soo-jung did not trust Dae-il and insisted they would know what it was only after opening him up.
During the surgery, Soo-sung discovered initials engraved on the liver that connected to Dae-il. The discovery made Soo-sung question Dae-il and his conduct.
Key Clues Hinting at Kim Ji-won's Finale Move
The four episodes have some clues hidden that prompt the audience to think that Soo-sung will expose her fellow colleague, Dae-il.
Clue 1: The Paper Trail / Medical Records
The most important clue is the mismatch between Dae-il's explanation of Kwon's liver and what Soo-jung discovers during surgery. The engraved initials provide strong evidence against Dae-il.
Soo-sung could trace the medical records and the original operation report that could become evidence of what happened during Dae-il's military service.
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Clue 2: The Shift in Dae-il’s character
Soo-jung is only committed to her patients. She does not care about approvals from colleagues. So, she was so desperate regarding Kwon's case, even though Dae-il was the one who saved his life once.
The exchange before the operation, where Dae-il tries to provoke Soo-jung by comparing her surgical ability to that of a god or a monster. She does not engage with his attempt to get under her skin.
This proves that Dae-il is not willing to go further with the operation.
Clue 3: Na Dae-il's Unravelling Control
Dae-il’s reaction to Kwon's emergency operation is another significant detail. Dae-il initially leaves the surgery to another doctor, but heads to the hospital when he learns Soo-jung will operate.
That behaviour change suggests he has a personal reason to fear what she might discover.
Final Verdict: How 'Doctor X' Will Likely End
The most plausible ending to the Kdrama is Soo-jung using the evidence from Kwon's surgery to challenge Dae-il. It could reveal his military past. This could raise a conflict between medical skill and ethical responsibility.
Another interesting possible ending is that Dae-il's exposure forces the hospital to confront its own willingness to trust a celebrated surgeon without questioning his conduct.
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Neither outcome has been confirmed by SBS. As of October 23, 2026, the series is still airing, and the finale's plot remains undisclosed.
FAQs
Q1. Will Kim Ji-won expose Na Dae-il in Doctor X?
A1. It is a leading theory that Soo-jung’s discovery of initials engraved on Kwon's liver will push her to expose Na Dae-il, but the outcome has not been confirmed.
Q2. What secret is Na Dae-il hiding in Doctor X?
A2. The drama reveals that initials linked to Dae-il were engraved on a patient's liver during an operation 15 years earlier. The circumstances and motive behind the act remain central to the conflict.
Q3. When does Doctor X Episode 5 air?
A3. Episode 5 is scheduled to air on SBS on October 23, 2026, at 9:50 pm KST.