I don't know if Egypt can be counted on to do anything other than what they want to do. It is a different country than it was 4 years ago.
Israel has asked itself the question: "Do we want to fight Iran now, or later when it has the bomb"?
A reasonable person can look at Iran's theocracy, their specific religious beliefs, and the statements of their rulers, and conclude that there is a good probability that Iran is building nuclear weapons, and that they intend to use them to attack Israel once they have them.
I'm sure that Israeli leaders have decided whether they want to fight Iran now or later. We will have to wait and see what they have decided.