They would never be allowed to launch them if it came to that. Russia hasn't used their nuclear weapons and if Israel started threatening it and they were at risk of being used or compromised it's more likely the superpower of the age would intervene and not to sure up Israel.
Interestingly the defunct apartheid regime in South Africa admitted that they developed nuclear weapons with the express purpose that they would use them to blackmail the west into intervening against an intervention by the Soviet Union. They then unilaterally disarmed after realising the dangers of that plan.
The solution that zionist Israel proposes is to murder Palestinians or drive them out of the land. For that is the way. If you want to avoid a retribution, the answer isn't more tit for tat it's resolution.
If Israel carries on it simply won't be safe for Jews to live in Israel. All of it's neighbours will hate it, and deservedly so. They are more likely to all be dead if they follow your path. And there probably wouldn't be much sympathy for refugees.