100 is my answer. Exactly my question to you:

What is your percentage to say no lets do not take actions. Because again; with this perspective every single action is legitimate. There is a chance for everything. If there is a weapon that can kill every human on the planet, every country will race to invent it because every country will try to invent it. Every action is valid. Every weapon development is okey, because if you dont, others will. You can kill everyone, because everyone might eventually try to kill you, there is always a chance.