It is the scene of Eko's death. 1. It's just a very emotional and awesome scene. 2. Now that we know how MIB thinks and that he is the smoke monster it makes a bit more sense and perhaps shows some light on why he disagreed with Eko and how he thinks of people. 3. Mad props to the actor who played Yemi because he was able to completely change over to the MIB when he says the line "You talk to me as if I am your brother" I think you can really see MIB in that line. Lastly, Eko does say that he "Saw the Devil" as his dieing words to Locke. You have to turn up your computer to really here him whisper it to Locke. Perhaps shedding some more light on the whole Jacob being good and MIB being bad idea.