"Source Code": Jake Gyllenhaal's Colter Stevens, heroic or dark in the end?

“So Colter Stevens, at the end of the film, begs Goodwin to let him take one more shot at sorting out this disaster on the train, stopping the bomb from going off. So he gets sent, he gets on the train, in what he discovers to be a parallel reality, stops the bomb going off, which means Sean Fentress is now dead although he shouldn’t be… Colter has basically forfeited Sean Fentress’ life just so he, Colter Stevens, can have a happy ending. I like that, because immediately although we have a happy ending, it’s ethically a little bit more ambiguous.

Duncan Jones, Jake Gyllenhaal and crew shooting "Source Code"

And Singer has some issue with this ethically ambiguous ending, not because it’s ethically ambiguous but because it’s hard to tell without these interviews with Jones that he intended such a dark concept. As it plays, he says in his original review, this “darker angle” is “kind of ignored,” while it still “suggests Stevens’ behavior isn’t quite as heroic as it’s made out to be.”Jake Gyllenhaal attending the Premiere Of Summit Entertainment's "Source Code", on 28th March 2011

In his follow-up last week, he details the spoiler more clearly, calling Jake Gyllenhaal’s character a “murderer” but one the film “doesn’t announce…very loudly.” He ponders this cloudiness:
So what’s more important: the director’s intent or the evidence on the screen? Jones wants those questions about Stevens’ actions to be present, but are they present enough? I’m not saying we need a shot of Stevens looking at Cloud Gate and crying “Oh no! What have I done?” But a little bit of a clue, in the editing or the music, could have made a big difference to the way we feel after the film is over.
Ultimately, though, Singer sees the work the viewer must do in the end as positive and fitting to the way Stevens’ mission turns out. Go read the final paragraph of his post for what he sees as a rewarding effort". Source: blogsindiewire.com

Still of Sam Rockwell as Sam Bell in "Moon" (2009)

-You’ve had strong leads in both of your films, first with Sam Rockwell who played three different characters in the film and now with Jake Gyllenhaal. What was it like working with him on Source Code?
-As far as I’m concerned what makes Jake such an interesting actor is that he will really go out of his way and try to experiment. Actors work so hard to come up with what it is they want to do with a role and how they want to be seen. As a director I want to let my actors do that and then suggest alternate ways to do it as well. Thing about Jake is that he tries everything. Because of this, we were able to take a more dower, serious story and inject more humor into it. This took the script in a different direction while we were making it, thanks to Jake’s willingness to experiment. Source: www.blackbookmag.com