Re: HR involvement
The few times HR has been involved in something affecting me, the outcome has not been in my favor. I would not consider them a helpful resource in a personal crisis. Their purpose, at least in the US, is to implement policy without exposing the company to legal liability (and administer the insurance plan). They are highly unlikely to take your side against higher management in any dispute, even if you think you have clear evidence.
They do, however, have the ability to irrevocably terminate my employment immediately, should they feel so inclined. And they're perfectly capable of making up any justification after the fact, and getting away with it.