Re: how did raikage avoid amateraus exactly?
Don't take my word for a fact, but Amaterasu is instant in 5 meter radius, and if the target is further then 5 meters from the target, then Amaterasu chases the target so fast that it's labeled unavoidable.
And it is true, you cannot escape it as long as the caster sees you. But Raikage is faster then Sasuke's Sharingan. Minato could probably dodge it, too, especially if he used Hiraishin.