Every time Colter goes back, the only thing happening is that the scientists are triggering what amounts to a dream based on the memories they extracted from dead Sean’s brain.

There is no new reality or alternate timeline being created because there is no time travel involved in the process at all… they’re just manipulating Colter’s brain in a way that looks kind of like that’s what is happening.

As you say, he does not return from the simulation automatically after 8 minutes… as long as he doesn’t die in the simulation, it keeps going. However, after 8 minutes, it’s no longer based on Sean’s memories. It’s just Colter’s brain doing what brains do when you dream.

At beginning of movie, in this ‘reality 1′ we see Colter 1 (as I will call him) being ‘activated’ for the first time and used to investigate the train crash. Goodwin 1 tells him at some point, ‘everything will be ok’.

When he is on the train, he becomes Colter 2 in reality 2 (ie one in which he is in Sean’s body). Of course he repeats this for (I think 7 times but exact number is uncertain) creating realities for Colter X in reality X.

It is important to note that Colter does not automatically return to the Source Code after 8 minutes. He manages to stay longer when he chased after motion sickness guy and only returns when he dies (run over by the train). Ditto later when he (and Christina) dies by being shot by the terrorist. In rest of realities, he dies at minutes because the bomb on the train kills him.

Each time he dies, his mind returns to reality 1. By end of movie, because he saves the train, Colter Z stays on in this ‘new’ reality Z. Naturally, despite his empty body being terminated back in reality 1, it does not affect reality Z. Should Colter Z die however, he will be dead, ie not returned to Colter 1 (which no longer lives).

So at end of the movie, we see Goodwin Z looking at Colter Z+1′s body, which has yet to be activated in reality Z.

What is the real kicker is that, Colter Z emails Goodwin Z to tell Colter Z+1 in future that ‘everything will be ok’ allowing Colter Z+1 to go try avert whatever disaster he may be asked to do so and then form his own reality Z+1. Remember Goodwin 1 says same to Colter 1? That’s coz reality 1 is NOT the first reality but one that existed after a previous Colter 0 has saved reality 0 and stayed behind in his ‘newly created reality 1′ and presumably told Goodwin 1 the same thing to tell Colter 1

Colter simply could not have made any changes to any past reality while he was experiencing what was really nothing more than a sophisticated VR world. Dr. Rutledge kept insisting that no actual time travel was involved and that no changes to the past were possible, and I think we should take that at face value. Frankly I don’t see how it could happen accidentally when all they’re really doing is playing back memories into a neural interface hooked into Colter’s brain.

Also keep in mind that if it was all happening in Colter’s brain, there’s ultimately no requirement that everything actually makes sense. They extracted eight minutes of memories from the train victim’s memory, so that’s where they were normally terminating the simulation, but maybe it doesn’t really have to end there; it just won’t be based on the victim’s memories after the 8 minutes are up. It’s essentially a dream from that point on, albeit one based on the foundation that the memories initially provided.

If Jake takes over the teachers body there at the end, to go live happily ever after and so forth, then when he makes the text message to capt. goodwin, and she walks by the room with the body being kept alive, and it IS still alive and breathing, as if it hasn’t been used yet, how is it still alive? Didn’t his soul transfer into the teachers body permanently? Who’s in Jake’s battle torn body laying on a table now?

Cali

I’ve seen quite a few posts in various places like StackOverflow from people who think ObjC is just fine, but I have to scratch my head and wonder how anyone can actually like this fugly language.

But beyond ObJC specifically, what really bothers me most about Apple development is that I DON’T HAVE A CHOICE. If i want to fully utilize OS X features, I MUST use ObjC — and that really annoys me. There ought to be a more language-neutral way to do it.

As for iPhone programming, thank God for Corona (a Lua-based system), or else I’d never get involved.