Plot hole: Sang-hwa forces a zombie inside a toilet stall. The zombie begins to bang on the door violently and Sang-hwa has to hold onto the door in order to stop the zombie from getting out. However, it is revealed later on that the zombies do not attempt to attack the humans or react violently or aggressively if they cannot see them. If this is the case, then this scene of the zombie banging on the door even when it cannot see any of the uninfected humans contradicts the rules that are established later on. (00:25:48)
Continuity mistake: When Seok-woo gets tackled by a soldier zombie at Daejeon Station, when he is first shown on the floor, he places his hands on the soldier's shoulders to keep him away from him. His hands are shown pressed against the shoulders in the first shot. When the camera changes to a different angle, his right hand is suddenly grabbing onto his clothing. (00:45:24)
Visible crew/equipment: When the zombie outbreak begins on the train, Seok-woo runs into one of the train cars that have no zombies, carrying Su-an with him. He places Su-an on the ground, and just before he does so, a yellow tape marker can be seen on the ground, allowing the actor to know where to place the little girl actor when he stops running. (00:26:27)
Visible crew/equipment: At the beginning of the film, when Kim enters Seok-woo's office, you can see the reflection of a boom mic in the glass near the top left of the screen. (00:04:35)
Continuity mistake: When the infected Yon-suk turns into a zombie, he begins walking up to the surviving passengers and Seok-woo puts his hands out to try and stop him. On the side of the train is the K-RAIL logo. In one shot, Seok-woo and Yon-suk are standing beside the edge of the logo. Then in the next shot, the two are suddenly fighting towards the centre of the logo, and in the shot after that, they are fighting away from the logo. (01:42:21)
Continuity mistake: When Seok-woo, Su-an and Seong-kyeong have escaped East Daegu Station, just after Seok-woo climbs back onto the train after kicking the zombies off, Seong-kyeong is shown hugging Su-an, holding her hair with her left hand. When the shot cuts, Seong-kyeong is suddenly touching Su-an's upper back. (01:40:20)
Continuity mistake: When Seok-woo walks to the rear section of the train after getting infected, he rests his head the back of the train. There is a light shown on the back of the train located a foot away from his head. The camera cuts then to an angle closer to him and his head is suddenly much closer to the light. (01:46:31)
Continuity mistake: When zombie Yon-suk begins attacking Seong-kyeong, Seok-woo puts his hand over Yon-suk's mouth to get him off. His hand is directly over Yon-suk's mouth at first, but when Yon-suk begins to bite him, it is suddenly Seok-woo's thumb over his mouth. (01:43:18)
Continuity mistake: When Seok-woo is fighting zombie Yon-suk, Seok-woo starts to get pushed over the handrail. Yon-suk has his left hand on the handrail, but when the shot cuts, his left hand is suddenly on Seok-woo's shoulder. (01:42:35)
Continuity mistake: When the zombies begin attacking the passengers in Car 15, the primary characters are shown reacting in horror in the vestibule. The homeless man has his hands raised in the shot from behind them, but when the shot cuts, his hands are lowered. (01:20:05)
Continuity mistake: When the surviving passengers are getting off the train at East Daegu Station, just after Yong-guk jumps off, he extends his arms to help Jin-hee whilst she is jumping off the step. In the next shot, Yong-guk is suddenly looking around and walking and Jin-hee is walking as well. (01:29:25)
Other mistake: The time on Jin-hee's phone is 1:56PM when she gets a text from Yong-guk. But later on, when Yong-guk calls Jin-hee's phone and Yon-suk breaks it when attempting to get into the zombie-free car, the time is 3:31PM. Only a handful of minutes passed in between these scenes. There's no way over an hour and a half could have passed. (01:03:25 - 01:09:47)
Continuity mistake: Just after Jin-hee gets the text from Yong-guk saying they are coming back, she gets up from her seat to tell the train attendant. Whilst she is walking up to him, she has the phone in her right hand. She then says "My friend is walking up from another car" and points backwards with her right hand and the phone is no longer there, it is now in her left hand. (01:03:30)
Continuity mistake: When discussing how to get through Car 11, Sang-hwa says "There's no way around it, let's go" and Seok-woo puts his arm over him, asks him for his phone and lowers his arm. At this moment, Seok-woo is shown kneeling about a foot away from Sang-hwa. When the shot cuts, Seok-woo and Sang-hwa are suddenly further apart from each other. (00:59:50)
Continuity mistake: When Seok-woo, Sang-hwa and Yong-guk realise the zombies cannot see them after the train goes into a tunnel, just after Sang-hwa says "Probably because of darkness" and Yong-guk replies "Yeah, I think so", the three of them turn around to look at the train car ahead of them. In the shot from in front of them, the baseball bat that Seok-woo is holding is tilted at an angle. When the camera cuts to behind them, the bat is suddenly at an upright angle. (00:59:35)
Continuity mistake: When Seok-woo, Sang-hwa and Yong-guk settle down after getting through the train car filled with baseball player zombies, whilst Sang-hwa is sitting down, Seok-woo is shown looking directly forwards. Sang-hwa then says "They stopped once we entered the tunnel, right" and Seok-woo is suddenly looking at Sang-hwa. (00:59:25)
Continuity mistake: When Seok-woo, Sang-hwa and Yong-guk are fighting their way through the train car filled with zombies, Seok-woo strikes a couple of them with a shield and blood splatters on the ceiling. In the shot immediately after the blood splatter on the ceiling, Seok-woo is shown trying to push through a group of zombies with the shield. The shot then cuts to Sang-hwa pushing one of the zombies, and behind him, we can see Seok-woo fighting with one of the zombies and doing something completely different to what he was doing in the previous shot. (00:56:45)
Continuity mistake: Just after Yon-suk gets off the walkie-talkie with the conductor saying "Full speed, no matter what", he sits back down and Jin-hee's phone starts ringing. On the row behind her, a man in a black blazer and a blue shirt that is unbuttoned at the top can be seen standing. In the next shot, as Jin-hee answers the call, the man in the black blazer behind her is suddenly sitting down. (00:53:10)
Continuity mistake: After the conductor gets off the phone with the control centre, the scene cuts to a shot from outside the window, of Su-an, Seong-kyeong, the homeless man and In-gil looking out of the window. The shot then cuts to inside and Su-an is suddenly looking at Seong-kyeong and the homeless man is suddenly looking off to the left. (00:51:30)
Revealing mistake: Whilst Sang-hwa is running towards the train as it is leaving Daejeon Station, he pushes over two soldier zombies with a shield. When the zombies land on the ground, it is apparent that their position on the ground is higher up than where the ground actually is. This is most noticeable when Sang-hwa runs past them, and the position of their bodies is almost level with Sang-hwa's knees. A Behind the Scenes featurette shows the two soldiers landed on a crash mat when doing the stunt, which explains why their bodies were higher up than they should have been. (00:50:36)
