There’s no way to talk about this movie without talking about the massive, gigantic, maelstrom of a plot hole at the center of this movie. So if you’re the sort of person for whom spoilers matter, get out now. This review is going to be nothing but spoilers.
This is a science fiction movie built around a central conceit, that after a massive train explosion outside of Chicago, they have the technology to send someone back into the memory of one of the passengers for the eight minutes before the explosion. It’s not time travel, it’s simply reliving the past. So they send the consciousness of a severely wounded soldier kept alive by breathing machines (Jake Gyllenhaal) into the man’s memory to try to figure out who the bomber is, in order to catch him before he can blow anything else up.
It’s clear from the get go the creators of the technology have no real concept of what they’ve tapped into. When Gyllenhaal is sent into the passenger’s memory, he also inhabits the man’s body. He doesn’t just relive the person’s life, he’s able to control it – to walk up and down the train, speak to people, investigate rooms the man had never visted before.
So clearly Gyllenhaal isn’t simply living in the man’s memory, he’s somehow ended up in an alternate universe: one where the explosion can still be prevented. The movie does not acknowledge this viewpoint through most of the movie, but logically, there’s no other explanation.
Now, up until this point, I haven’t given you too many spoilers, but this is where things are about to go off the rails (ha!) of standard movie reviewing. Let’s talk about the ending. Get out now if you want to watch the movie someday.
All right, everybody ready to move on? Are you sure? Let’s go.
At the end of the movie, after numerous failures, Jake Gyllenhaal finally figures out who the bomber was (shocking, I know), but he isn’t able to stop the train from exploding. He’s certain that with another trip, he can succeed at stopping the bombing. The operators of the Source Code are reluctant to send him back in again – they already have the information they need, so what’s the purpose of the sending him back? He can’t change the past. Gyllenhaal, understanding that the trips he’s being sent on are not to the past, begs until one of the engineers (Vera Farmiga) finally obliges.
Once back on the train, Gyllenhaal defuses the bomb and captures the bomber. Eight minutes pass and…. nothing happens. The train arrives in Chicago. The passengers exit, and Gyllenhaal continues on, living in the man’s body in this alternate timeline.
…wait. So, what happens to the guy whose body it was beforehand? I don’t know. He disappears. Every other passenger on the train survives and continues on with their lives, and this poor guy is up in Heaven, trying to explain things. “Yeah, Jake Gyllenhaal is living in my body now, hitting on my girlfriend. Don’t really know what happened.”
Not to mention, there’s already a version of Jake Gyllenhaal in this timeline. So Gyllenhall writes a note to Farmiga, thanking her for sending him back into the Source Code (in another timeline that she isn’t aware of). He tells her that the efforts of her alternate timeline-self helped stopped a train explosion this morning, and asks her to mercy-kill the version of Gyllenhaal living there in that timeline as a favor. This seems mean of him, because he’s ruining any chance of this-timeline’s-Gyllenhaal getting to get put into the body of some other poor sap and resurrected in a different timeline, but it is his own life (sort of), so I guess I’ll allow it.
She obliges, which means that in this new timeline, we have a living Gyllenhaal (in someone else’s body), a dead Gyllenhaal (in his own body), plus the soul of this train passenger that’s still out there somewhere. In the original timeline, we now have no Gyllenhaals (not even Maggie!) – just a wounded body with no consciousness. Odd place to leave a movie.
Not to mention that, if the movie’s ending means that we’ve established that Gyllenhaal was tapping into a series of alternate timelines. So each time he failed to solve the puzzle, all of those people died. If he’d figured things out faster and spent less time trying to call his dad, several thousand more people would be alive. That’s a lot of times he allowed Michelle Monaghan to die. More than I can really forgive.
All that said, it was a pretty good movie (you weren’t expecting that, were you?). Gyllenhaal, Monaghan, and Farmiga are all really good in it, and the film feels the way thrillers are supposed to feel: like a puzzle slowly being put together in front of you. It’s a very well-directed picture, and I enjoyed myself a great deal. Go ahead and see it.
Just… try not to think too much. It’s only gonna bug you.