Don't know how it got there but didn't Jack tell Kate when they first got on the island the story of the 5 tattoo . About that operation , the story she had to tell him on the walkie talkie ..... And if Ethan were a surgeon why would they send him to spy on the losties if he were so important and take the chance of him getting hurt/killed etc.....

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If I could wake up in a differant place , at a differant time , could I wake up as a differant person ? ? ? Tyler Durden