Question about old Joe's motivation
I've got a question concerning old Joe's motivation, for killing the Rainmaker.
Was his motivation either:
1. Killing the Rainmaker, to potentially change the outcome of the future, so he - when he shot the Rainmaker, would suddenly return to China in the future again (just as he disappeared when young Joe shot himself) with his wife, who - because of his act then would be alive, because he indirectly had taken care of the henchmen, who in the future was sent by the Rainmaker?
Or...
2. Did he do it, so young Joe would live the exact same life he did, but wouldn't suffer the loss of his then future wife?
The reason why I'm asking, is because the movie/script sort of gives 2 different answers to this. When they're sitting together in the cafeteria, old Joe is telling young Joe he doesn't know *beep*:
"Shut your *beep* child mouth.
She's going to clean you up and
you're going to take her love like
a sponge and you're both going to
pretend that she's saved you,
you're so self absorbed and stupid."
- which gives the impression, that he's actually doing it for young Joe's sake, so he's still gonna meet her etc. etc., but isn't gonna suffer the loss of her being murdered by the Rainmakers henchmen.
But later on in the movie, when young Joe is explaining the situation to Sara, he's saying:
"I think... he thinks, the instant
the rainmaker dies, he'll never
have been sent back, so he'll just
vanish, and be back with his wife."
- which gives the impression, that he's only doing it for his own sake/of selfish reasons.
What is your opinion/view?
All these voices in my head, and not a single one I understand.