You guys are right the dynamite thing is dodgy, but it's the best they could do on short notice. I don't know maybe if they had gotten all the wiring done, it would have been a good game plan. I think that Ben might know where the losties are going (radio tower) according to the info he got from mikhail on naomi. I wonder if Ben really thinks the looking glass is flooded. Mikhail could have also told ben that sayid had many maps of hatches on the island, that could have also tipped Ben off that the losties could shut off the jamming signal, and knows where they'd be going to create a new rescue message. I don't know why i am defending juliet, but I am. I believe that the fact she wants to get off the island makes her a lostie not an other.