Mrs. Hawking has tried several times to avoid killing her son, but she was never successful. Just like Desmod could not avoid Charlie´s death.. What ever happened, happened. The question then is: Is there any point in the future that has not happened yet? I beleive this moment was not yet shown, and probably this is when things can be changed. This would be why Mrs. Hawking is now "lost" she knew everything that could happened until she sent everyone back to the island, but now the next moments are the ones that has never changed.
Jack´s action will not avoid the plane to crash and everything that happened, maybe a little change in how things happened, like what happened with Charlie. He did not die with an Arrow through the neck, but he died anyway. The incident might not be the same, but it will happen.
The answer why they went back to 1977?
Because Mrs.Hawking tried to change things to avoid his son death. And as she explained to Desmond, destiny corrects its course. The way to correct something that Mrs Hawking might have tried to change, was to send them all to 1977 and make the Incident occur anyway.
Why Sun did not go with them? That´s though to answer.
Jack´s action will not avoid the plane to crash and everything that happened, maybe a little change in how things happened, like what happened with Charlie. He did not die with an Arrow through the neck, but he died anyway. The incident might not be the same, but it will happen.
The answer why they went back to 1977?
Because Mrs.Hawking tried to change things to avoid his son death. And as she explained to Desmond, destiny corrects its course. The way to correct something that Mrs Hawking might have tried to change, was to send them all to 1977 and make the Incident occur anyway.
Why Sun did not go with them? That´s though to answer.
