Indiana governor election 2016
Republican (Holcomb) gets 51.4% of the vote. Democrat gets 45.4% of the vote
Let's say those aggregate percentages remain the same, and Rainwater comes on strong to overtake Holcomb
If Rainwater gets 26% of the vote to Holcomb's 25.4%, who becomes governor? Not Rainwater or Holcomb. What you need to ask yourself is, do you think Rainwater can exceed that 50% of the vote you're talking about; or more broadly, which of those two is more likely to exceed 50% of the available vote?
Or more simply, "Do you feel lucky, ..."
The only flaw in your calculation is that you are making the assumption that ZERO dems jump ship and ALL Rainwater votes are taken from Holcomb. We cant quantify a number yet, but to assume Meyers keeps 100% of his voters is incorrect. Its not that cut and dried.