Leiberman, What was the plan?

Leiberman was the one that started the break of the previous coalition. He left stating that Netanyahu was not fit to lead. But here he is again entering a coalition with him one more time. Did he really think that he can become PM bc he left in a huff over the security situation? In hindsight he definitely made the wrong choice. But how does he pick up from here? If he was true to his word he should recommend Gantz for PM (which he is not) and sit in the opposition, waiting for the next election that Netanyahu will not be running in. What was his plan?