Just to continue that last posting about Jack’s illness:
What if Juliet wasn’t taking something OUT of Jack, but was putting something IN to Jack? Drug Jack up, get him thinking he has appendicitis, and throw one of those Claire devices in there. I thought I’d just throw that out there as an additional possibility.
Oh, and that scar that isn’t there when Jack was in his towel? No scars when the island heals you.