In episode 3 of the TVING original series "Yumi's Cells Season 3," a scene was depicted where Yumi, played by Kim Go-eun, develops feelings for Sun-rok, portrayed by Kim Jae-won.

In this episode, Yumi and Sun-rok took a train trip for a book concert. Sun-rok hurriedly left without washing his face, and although Yumi suggested he sit next to her, he chose another seat first. Later, when Yumi approached him and asked, "Do you not want to work with me?" Sun-rok explained that he had to leave the team because his schedule overlapped while managing multiple teams. Yumi responded, "Isn't that just an excuse? I've been patient enough. I'm not usually someone who gets this upset, but lately, I've been really annoyed," which made Sun-rok look flustered.

Sun-rok got off the train to make a call to the editor-in-chief and ended up falling behind, leading Yumi to suspect that he intentionally avoided the train. However, Sun-rok texted Yumi to inform her that he fell behind while on the call, and Yumi replied that she would take care of his luggage. Waiting for Sun-rok, who arrived on the next train, Yumi felt a flutter of excitement upon his appearance. Sun-rok explained to Yumi, "Earlier, I couldn't give you an answer, but it is true that my schedule got tangled. There is no other reason. If you misunderstood, I apologize."

Yumi's cells showed various reactions to Yumi's changing feelings toward Sun-rok, including "Where did the love cell go?" "Yumi's Cells" is based on the webtoon of the same name, and in season 3, it depicts Yumi, now a star writer, falling in love again through an unexpected encounter with someone.