Israel and Iran may have just broached a new rapprochement, and it shouldn't matter if each side has ulterior motives.
It would be hard for anyone to know all the reasons and ramifications regarding Israeli Defense Minister Moshe Ya'alon's decision to remain in the hall when Iranian Foreign Minister Javad Zarif delivered his presentation. But there's certainly room to calculate the stakes.
Israeli Prime Minister Benjamin Netanyahu and most of his cabinet maintain that Secretary of State John Kerry's current negotiations with Iran are a "historic mistake". Staying to listen during the annual Munich Security Conference - which tends to be more about military cooperation than political grandstanding - seems like a good place to push the envelope and show some nuance.
For Ya'alon, who rather publicly dismissed Kerry's framework for Israeli-Palestinian peace, this was also an opportunity to show that 1) he is not averse to all diplomacy; 2) he doesn't need any American prodding to act like an adult; 3) even one of Israel's most forceful opponents of diplomacy may be ready to play for the right price; 4) Israel faces more pressing existential threats than the Palestinians, namely Iran.