Flying might be impossible and probably would be dangerous. Boat travel sounds horrific to me.

I like Canada and I could seem them doing a decent job of harboring refugees, but I think I would
go with Mexico, eventually making my way down to South America.

Staying in the country would depend on
A.) the nature of the attack(s),
B.) who carried them out and
C.) whether we agree with why they were carried out.

My first course of action would be using my savings to relocate as many loved ones to one city as possible.
We'd hunker down with provisions,
combine our assets and suss out A, B, and C.