Question

is the point of a narrator to provide one steady view of a action? why or why not?

Answer 1

The narrators are the protagonists in the stories. They are restricted in their knowledge to what they can possibly know without violating the rules of probability. The function of narrating a story can also be split up between two or more characters in the text, who give different evaluations of the same events. This can also be achieved by means of letters and messages, for example

Answer 2

No, it isn't. There's plenty of stories that mix between Third Person and First Person. A good book that shows this is Nikolski, by Nicolas Dickner. 

I hope this helps! ~Mia