The only place I could find to watch this movie was a streaming service with ads. I HATE ADS!!! This is a thriller. Stopping in the middle of suspense, repeatedly, for 7 ads at a time is a momentum killer. (I had to get that off my chest - grrrrr!). Did the movie survive the interruptions? I was so involved in the drama that I shouted at the screen when ads interrupted it, so I’m going to say it did well as a thriller. I am following Bae Doo-na’s filmography, and she did not disappoint. She is such a talent. The primary performances were the man who was trapped and the engineer who was trying to rescue him. Both performances were great. The social commentary is worth mentioning because it posted the question, “What is the value of a person life to a nation?” I give this movie a 7 (good suspense) out of 10. It may have deserved more if my viewing experience hadn’t been so frustrating. [Thriller]