Nothing. Scalia is not referring to what you think he is. You are misinterpreting his words.
Seriously, look at those words again. “If, even as the price to be paid for a fifth vote, I ever joined an opinion for the Court that began...”
What price is paid for a 5th vote that he is talking about?
It can’t be hiding his head because that’s his reaction to doing all this that he thinks is so stupid.
If I had to join the democrat party in order to endorse abortion, I’d hang my head in shame.
If, as the price for getting their $5 walking around money, I had to join the democrat party , I’d hang my head in shame.
I think he’s definite hinting there’s a benefit to being the 5th vote.