The fourth episode of "As You Stood By" commences with Eun-su and Hui-su engaging in a gruesome practice session, strangling their supposed victim, Jin-pyo, with a rope and...a pillow. The real Jin-pyo enters the scene, piecing together the gruesome scenario. He launches an attack on the women, narrowly missing taking Eun-su's life before Hui-su strikes him down with a snow globe, crushing his skull and extinguishing his life rapidly. Hui-su's fury transforms into a paralyzing fear of being caught, and she begins to hallucinate blood everywhere, even on unscathed surfaces. Eun-su takes charge, tidying up the mess and confirming the next steps with Jang Kang.
The downstairs neighbor pays a visit to check on Hui-su, but Hui-su sends her away before the woman can see the blood on her dress and Eun-su's bloody feet. The neighbor decides to turn a blind eye to Hui-su's actions and ushers her husband and child out.
Meanwhile, the Chinese workers are enjoying a team dinner, with So-baek attempting to extract more information from Jang Kang regarding his involvement with Eun-su. Jang feigns ignorance, and So-baek drops the subject.
The next morning, Jang Kang arrives at Hui-su's place, unaware of the true nature of the situation. He changes into a suit and wears Jin-pyo's watch, while Eun-su makes him carry a suitcase containing Jin-pyo's body to her car. A sweeper notices Eun-su's car thanks to a parking fine.
As they depart, Jin-young appears to freshen up, noticing Jang Kang's old shoes but mistakenly believing they belong to Jin-pyo. She doesn't bat an eye at Hui-su's bruises or her fidgety behavior. She finds blood on some tissue but dismisses it as coming from her uniform, and sees the cracked snow globe but erroneously assumes Jin-pyo beat Hui-su with it. Jin-young is undergoing a Presidential Office evaluation that includes a family background check, and she texts him to keep a low profile with his affairs and abuse until she gets in. However, the phone is in Eun-su's possession, who deletes the texts and gives it to Jang Kang. He withdraws money from Jin-pyo's bank account before passing through airport security, where Hui-su exhales a sigh of relief and starts cleaning out the place of everything she hated.
The scene shifts to the solemn task of disposing of the body. Eun-su receives yet another parking ticket, but the security guard relents upon recognizing Hui-su. As they drive off into the woods, Hui-su compulsively scrubs at her hands, as if cleansing them of an imaginary stain. Eun-su attempts to soothe her, but their journey is interrupted by a tragic accident: a collision with a deer. The guilt weighs heavily on Hui-su's mind, conjuring up vivid images of Jin-pyo's lifeless form.
Their path is again interrupted by a couple on a picnic, their presence adding to the already tense atmosphere. After burying Jin-pyo's remains, they cast the snow globe into the sea and pay a visit to Hui-su's mother. Their escape leads them to a seaside town where Hui-su indulges in foods she had been denied with Jin-pyo by her side. However, her overzealous consumption results in a moment of retching, prompting Eun-su to realize that the restaurant's CCTV cameras are silently watching them. To lighten the mood, Eun-su buys firecrackers, and they revel in their own brand of mischief before retiring for the night in their car.
The following morning, as the couple frolics, they inadvertently tread on Jin-pyo's grave, disturbing the earthy tranquility. They brush it off as a mere oversight, but the bloodied leaves serve as a stark reminder. Meanwhile, the girls power up their phones to find their devices inundated with texts and missed calls. Fortuitously, Jang Kang has made it safely to China; unfortunately, Jin-pyo's mother is left reeling from his sudden silence, her calls going unanswered.
Their return journey to Seoul is further complicated by a roadblock caused by a separate accident. As the traffic cops guide the cars through the chaos, one officer notices the deer blood on Eun-su's headlights and the telltale bruises on the women's faces. He demands they open the trunk, setting off a panic as they realize it contains the shovels used in their desperate act.
