That totally shocked me. I think it could be one of two things with Michael, either he's trying to rally them against the Others, but still not sure why he killed AL. Btw, I think I mentioned that I found something out by mistake, well that was it. I was also shocked when he panicked and blew Hurley's bird, poor Hurley. Obviously he's framing Henry (we'll just call him that) so that this further distances the survivors from the others. I don't know if you can recall what Henry said to AL, had she been captured by the others and someone tried to change her? I didn't catch it right. Maybe that's what's happened with Michael also, but he has been converted, not sure, still think your it could be the rally.
Also if you remember Henry said to Locke that he was good and they where coming to get him, if you notice the good people, without the demons i.e. Locke, Hurley's Bird and Rose have seen their lives dramatically changed by having their illnesses etc totally reversed. I'm wondering if the kids are being kept away from the bad eggs (they're not really bad, but have had their dark moments i.e. killing people etc).
It's all hotting up now it seems.
FD