Jack's drive to blow up the Others seems odd and out of character to me. Perhaps he is just so pissed that even after helping Ben and peacefully coexisting with the Others for a week that they would continue plotting against the Losties, but the solution of exterminating them seems way over the top. Also interesting how he is so much more intent on blowing them up than establishing communications with the outside world. I noticed that Kate even gave him a look at one point that was like she didn't understand where his bloodthirstiness was coming from.

Could it be that Jack is so zealous because he's setting up the Losties? Maybe he thinks the pregnant women would be better off in the Others' hands and he's about to betray them. My hunches are usually wrong, but does anyone else still think there's something "off" about him?

I'm VERY suspect!! I think They are setting him up for a major betrayal.

I still think:

Jack made a deal with the others, and he is in fact delivering the entire camp to them in one fell swoop.