Each to their own but I think it was a smart move. If he got rid of Locky, Tara would be getting her guard up and that final 2 deal might not work out.I personally don't see that question as masterful. If you look at the overall picture Peter isn't the threat you should be worried about. He hasn't played, he's existed.
IMO he should have eliminated Locky (whose vote for Tara win is a 100% lock)
Others on the jury he may be able to sway. With Tessa though, I think she would give her vote to anyone against him in the final if he were to get there.