What is really happening in Source Code?(spoilers duh!)

This movie has me scratching my head.:confused:

1.The scientist is flat out a liar, he lies about the eight minute limit(proven a lie because two of the trips last longer than eight minutes aside from the end) to keep our hero from the temptation of living forever in the alternate reality. He also lies about the nature of the Source Code project to stop our hero from attempting to save people and focus on the mission, that gobblygook about afterglows and the memories is bullshit. For one thing how on earth did a human brain survive that blast? It didn’t, he actually found a way using quantum mechanics or something to create alternate timelines.

2.The scientist doesn’t know himself and is making assumptions, I don’t believe this.

3.The main reality in the movie is already an alternate reality created when some disaster before the train was averted, and in the reality at the end of the film our hero is living in a future crisis will be the first to be averted by the Source Code project.

4.The film’s script underwent rewrites or development issues so that things got confusing, which might explain the title which doesn’t make sense?
Anyone else want to take a stab? I really feel since the film goes out of it’s way to contradict the explanation given we can safely assume it is BS.

The scientist thinks he is creating a sophisticated simulation using the dead guy’s brain as a target, but actually the technology ends up targeting alternate versions of him in other universes.

He doesn’t think the simulation will work past the time the original guy died, but because the alternate doesn’t die, he’s able to stay.