While I wasn't there, I've come to the conclusion that Kerry freaked out that day and it became the straw that broke the humps back.
That is why he wrote up a AAR that would get him out of town. He couldn't handle it. Kerry is not a real world person. It's like Walter Mitty meets the Viet Cong.
Having fled not only the scene of the mining of PCF-3, he also fled VN. He was so envious of those that could cut it he took to undermining them and maligning them in front of congress. He's a very bitter 6'4" little man.
I expressed the same thoughts some time back. I think he is a coward