Me and my girlfriend have a zillion ideas, but I will put it out as a few questions...

Why does Jacob need John's help?

Why is Ben the only one in touch with Jacob?

Is that line of sediment used to confine Jacob? (Voodoo/Santeria style?)

Why did hearing that Jacob asked Locke to help him seem to scare the bejeezus out of Ben and prevent him from further perforating John with bullets?