Megyn Kelly has reached her limit with Fox News in general and Bill O'Reilly in particular.
Variety:

Kelly challenged O’Reilly’s repeated assertion that no Fox News employees ever filed complaints against him with management or the company’s human resources department. Kelly said she emailed then Fox News co-presidents Bill Shine and Jack Abernethy regarding O’Reilly’s CBS appearance.

“I wrote, in part: ‘Perhaps he didn’t realize the kind of message his criticism sends to young women across this country about how men continue to view the issue of speaking out about sexual harassment,” Kelly said. “Perhaps he didn’t realize that his exact attitude of shaming women into shutting the hell up about harassment on grounds that ‘it will disgrace the company’ is in part how Fox News got into the decade-long Ailes mess to begin with. Perhaps it’s his own history of harassment of women which has, as you both know, resulted in payouts to more than one woman, including recently, that blinded him to the folly of saying anything other than ‘I am just so sorry for the women of this company who never should have had to go through that.'”

Kelly closed her segment by taking direct aim at Briganti, a 20-year veteran of Fox News.

“Women everywhere are used to being dismissed, ignored, or attacked when raising complaints about men in authority positions. They stay silent so often out of fear. Fear of ending their careers. Fear of lawyers, yes. And often fear of public shaming, including through the media. At Fox News, the media relations chief Irena Briganti is known for her vindictiveness. To this day, she pushes negative articles on certain Ailes accusers, like the one you’re looking at right now. It gives me no pleasure to report such news about my former employer, which has absolutely made some reforms since all of this went down. But this must stop. The abuse of women, the shaming of them, the threatening, the retaliation. The silencing of them after-the-fact. It has to stop,” she said.

The "silencing of them after the fact" happens because in exchange for a cash settlement those who step forward with reporting their sexual harassment are forced to sign non-disclosure agreements. Trump has been protected by those for years, not only in terms of sexual harassment but also reports he used racist language on the set of The Apprentice. Trump's campaign made phone bank workers sign NDA's as well. Who asks phone bank workers to sign NDAs ahead of time? Trump does.

And a word about Irena Briganti. That Megyn Kelly mentioned her by name is huge. The Washington Post told the story of the Kelly-Briganti falling out in July of 2016:

Briganti has worked indefatigably on behalf of Kelly, wiring up favorable profile after favorable profile for the prime-time host in publications like the New York Times Magazine, Variety and Vanity Fair. The imperative behind that work is to position Kelly, a redoubtable talent, as the face of Fox News. Oh well, New York magazine’s Gabriel Sherman this week reported that Kelly told those investigators from Paul, Weiss that Ailes had sexually harassed her about a decade ago. Amid all these stunners, Sherman also cited “sources” as indicating that “Briganti has been criticizing Kelly to reporters, saying she is selfish to not stand up for the man who gave her career opportunities.”

Career opportunities in television and movies that so clearly included staying silent on bullying, harassment, and even rape -- because women's bodies in the "industry" are commodities on and off the screen. This must stop, but it will take a very deep stabbing at the culture to get there and include outing of women collaborators like Briganti to do it.

Good going, Megyn. For once, I believe you showed actual courage to stand up to the zeitgeist of your industry. We won't forget all the "Santa Claus is white" nonsense you said on the air as part of your job at Fox, but today you showed courage.