What is the last line of Chapter One? Paraphrase it.

I been silent so long now it's gonna roar out of me like floodwaters and you think the guy telling this is ranting and raving my God; you think this is too horrible to have really happened, this is too awful to be the truth! But, please. It's still hard for me to have a clear mind thinking on it. But it's the truth even if it didn't happen.

Basically Chief Bromden is saying that he refuses to be quiet about McMurphy's story. He is going to tell everyone the truth even if others deny it. People must open there minds and except the truth because he finally has something to say.