Well, there are problems with the whole setup. Michael knows he's to be murdered New Year's eve, but he still hangs around. Why? If he's got a plane standing by, why not leave earlier that night or day? His plan to murder Roth does not require his presence on the island; in fact, his absence makes much more sense. He doesn't know that Batista is going to abdicate. Thus, he knows that once Roth's (or Ola's) body is found, he's a primary suspect whose murder by the military is planned anyway.