Even if “Source Code” casts him in an action/sci-fi variation on “Groundhog’s Day,” Jake Gyllenhaal isn’t fantasizing about any personal life do-overs. He rather use a time-rewind to do good for others.

“I’ve lived a blessed life,” says the actor, who plays a character who must continually re-explore eight minutes someone else’s life in order to avert a major catastrophe. “I think with regret, regardless of what it might be, if you listen to it is the best teacher, in the way that it has allowed me to live more presently.”

“But in the wake of something like what is going on in Japan, even around the world,” Gyllenhaal continues, “I can’t think about something that I would want to go back and re-live in my life, because my life has so far been pretty extraordinary. I would want there to be something like this computer program in the movie: Imagine if you had the ability to go back into a nuclear scientist’s body in Japan, or eight minutes before something happened – you could warn thousands of people what was going on. That’s what I would use it for. It’s hard for me to think about something for myself in the situation that is going on right now.”

Gyllenhaal says shooting the structure-bending “Source Code,” directed by “Moon’s” Duncan Jones, was a treat despite his character’s return to the same eight-minute time sequence because each step forward in the story gave each sequence a fresh new set of action, drama – and a little comedy, to both illuminate the audience and build greater suspense.

“Because Ben Ripley had written such a tight script and because each Source Code had a specific theme, we named each Source Code [sequence] chapter by chapter,” the actor says. “So the first Source Code was like ‘Absolute Confusion’ and we could make it the more confusing, the better. The second one was very clear and so on and so forth with the different themes. And so knowing the second one was the same, Duncan would come up to me and say: “Make it weirder – treat everyone like they’re a computer game. Respond to them even stranger.” And because we had these clear set rules, we could than vary it…We were constantly thinking about variation and I think that’s what makes each time you go back so intriguing. By the second one you know you’re not entering or exiting the same way.”

Gyllenhaal admits once he had his brain fully wrapped around the story’s tricky twists, he does wish he could’ve gone back to earlier takes to add extra, subtle little hints of what’s ahead for sharp-eyed repeat viewers of the film to spot. “With every clue you put in, you know someone could come back and watch it again and go: “A-ha!” And I had those “A-ha!” moments, while we were in the third Source Code about the first Source Code. It’s constant process of exploration.”