Young Joe doesn't know exactly what's going to happen though and without making Old Joe disappear, he is 100% killing the mom. Did you see how far away Young Joe was from Old Joe? Remember the comments about the Looper gun? No way he could have reached/killed Old Joe before Old Joe killed Sara and started the "loop" of Sid becoming the Rainmaker.
I think it was pretty ingenious.
Huh? Yes, I know young Joe isn't close enough to shoot old Joe. But he IS able to see what happens. He KNOWS that his older version kills Blunt's character which supposedly is what makes the kid grow up to become a monster. That is why he kills himself. As he says, he sees a man who stop at nothing to save his wife. And a kid who, because he grows up without his mother, becomes a monster. It's a circle, a cycle. So he decides to change the cycle by shooting himself. My question is why is that even necessary since HE KNOWS what he's going to do so all he has to do is not do it. The movie Minority Report went into this. Because you know your future, you have the ability to change it. But young Joe doesn't try that.
I also wonder if it's even necessary because old Joe just KILLED everybody at the syndicate. They are all dead it appears. So doesn't that mean no more loopers and wouldn't that in itself change everything?
I love the movie. Especially the ending. The last 20 minutes of the movie are unbelievably fantastic but I do wonder about that.