How does he do this? He visits the memory of one of the victims of the last 8 minutes of their life, he has to keep going back to find out certain information and suspects to prevent another attack from happening, and each time he only has 8 minutes before the train goes BOOM.
Simple? No there are many twists in the film, but what I like most about it is it always is making you think, similar to Inception, even after the film, its pretty deep I have to say and you never know when the film is going to end or how its going to end.
I give it an 8.5 out of 10