If you knew that something big like a limited nuclear war

If I knew, so would everyone else. A lot of the 'armageddon' films assume all the services needed (water, telecommunications, planes, etc.) will be merrily serviced by lots of people who are unmoved by the coming catastrophe. I don't think running away will be possible as the roads will be gridlocked, the petrol (gas) stations will cease functioning as deliveries will cease and everyone will want to spend time with their loved ones if they can.

I will prepare myself and my loved one to meet my Maker while trying to make plans for survival as best I can.