I don't think it justifies any of her actions at all, but I think the notes validate that KK's fears were real (something I had discounted as well), and I hope that makes her a more credible witness in every juror's eyes, if that was the only thing holding anyone back in any way.
It's also pretty telling how PF views a woman who dropped everything, did his horrible clean up work, participated in his fake phone text and call games, helped him cover up a crime, likely because she only wanted to be with him -- and he views her with absolute contempt, disdain, hatred, and delights in charming graphic detail of how he would want to see her dead.