Exactly - it's too late to save the land/people of Israel if Iran sends a nuclear bomb. One bomb would kill everyone in Israel, either immediately, or due to extreme fall out. If you have seen pictures of the people of Japan after one of the nuclear bombs we dropped on them, some disappeared as their bodies were totally destroyed, other had their skin falling off, they died, and others kept dying for many months due to radiation.
Israel knows the above and I think they WILL send the first nuclear bomb in order to stay alive as a people and country.
Dunno... Iron Dome seems to be working pretty well for Israel right now, and it would have plenty of warning on an ICBM. Saudi Arabia with no Iron Dome has a lot more reason to be nervous. They have Mecca and any serious jihadi country would literally kill for it. Saudi Arabia might end up begging Israel to help it attack Iran.