There is a 0.0% chance that Israel will not retaliate. If negative percentage chances were a thing, I'd say less than 0.0%It could be that they have assessed that "hitting back" is not the smart response. An escalated regional conflict with a nation-state like Iran is a very different matter than a conflict against a terrorist organization like Hamas or Hezbollah, particularly one that could achieve nuclear breakout in a matter of weeks.
Hopefully, cooler heads will prevail.