The picture of Eko as a kid who is selling drugs is a perfect example of how things can play out differently in alternate timelines, yet, the overall fate of major events can't be altered. When you go back in time, you can only “change” things that don’t have an impact on your destiny. In other words, if you went to go see a movie on a specific date, and then went back in time, you wouldn’t necessarily go see the movie the second time around. However, if that movie caused you to make a life-altering decision, fate would find a way to have you still make that decision, just without the original influence from you going to see the movie the first time around. Being a drug dealer is a part of who Eko is and shaped his destiny. So in any timeline "the universe will find a way of course correcting" and Eko will be what Eko must be - a drug dealer.

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