Random thoughts while watching the movie:
- Why the F did he honk 5 times? He could've stopped after the second one; Jeong Su already called them on the phone and said he heard a car's horn honking. Also, bringing a clumsy rookie with you when there's a life on the line... Pretty reckless.
- Lol, when the 안전한 ("safe") part of the sign fell down after the second collapse.
- I can somewhat understand why doesn't he turn off the phone (he can have an incoming call from Kim Dae Kyeong anytime), but I would at least turn on the battery saving mode and put the brightness level on the lowest.
- Literally after Mi Na said she wanted to make a call, Jeong Su started dialing. She didn't even say the number she wanted to call, lol.
- It's fine and all that they have a little to drink (and Jeong Su a little to eat), but where do they do their other... needs? Especially Mi Na. Jeong Su can somewhat easily get out of his car to pee/poo, but Mi Na has no options. [Okay, nevermind that. :'c]
- Jeong Su should've checked her pulse first when she didn't respond. That way he could've saved some more water.
- He could've been really bored (and stupid) to try the dog's collar on and even press the button. :'D
- Is his wife alright? She dares to threaten him (don't even try to deny it, Se Hyeon) when he's been isolated, seen a woman die, is dehydrated and starving for almost 3 weeks? WTF is wrong with her?!
- Driving through a tunnel right after his trauma? Man, I wouldn't wish anyone a wife like Se Hyeon.

The movie started out really good. I think it went a little downhill a bit after Mi Na died. They dragged this story on too long, so it became more and more unrealistic as the minutes passed. Realistic is Mi Na's part. You can't survive for more than a month basically alone, without any food, drink and major injuries in a collapsed tunnel - let alone when they blast two pack of TNTs near you. (Don't even get me started with the dog's survival skills.)

Still, it was pretty enjoyable. It kept me on edge several times, and the acting of Ha Jung Woo was amazing. And with all those cool effects and camerawork, it was even more realistic.
Like I mentioned, I would've liked it more if this was at least a little shorter, not dragging on the plot for 30+ days, but it was still a good movie. The ending was a bit abrupt, though.