Well, I'm certainly not a counselor but based on my own experience with a *very* staunch WAS and all I have read here I think you are giving yourself false hope if you think her being pissed means she is still invested.
She is pissed because (for now) she is done and you won't let her be done. She wants out of this marriage and she is pissed because she is still in the marriage. She was pissed at the flowers you sent her because it indicated you are STILL pursuing a romantic R with her and she doesn't want that. The longer you string this marriage out that she doesn't want, the longer she will stay pissed and her resentment will deepen.
Sometimes a WAS showing anger can be a good thing but her actions (to me) say otherwise. She wants out and you are holding her back. Her letting go of anger does not mean she will want to work on the marriage.
You don't need to know anything from her - you may WANT to know stuff but you don't need to. She doesn't want your help except to sign separation/divorce papers. The problem? You don't want to help her that way so the anger will continue to build.
