After tribal, I expected the winner but
They were almost certain the vote was going to be 3-4 against them. A better tactic would've been to stay quiet, let the vote go on, and they split their three votes 1-1-1 (Philip, whoever and whoever, probably Phillip's presumptive final 3). Then reveal they were all immune before the count, forcing the seven to vote one of their own with no advance discussion. The amigos could then attack Phillip en masse, and unless the other 4 all voted for the same non-Phillip person, he'd be gone anyway. But this "stealth" way shakes things up a bit more, and gives the amigos more cracks to wedge their fingers into.