“I will say I am going to expose the corruption that went on in the campaign and in the White House. I’m going to continue to blow the whistle on all of that,’ she said on MSNBC Tuesday.

That’s what’s exposed her to such a visceral reaction from Trump. He has singled other former staffers out for scorn, but Omarosa Manigault Newman has been on the receiving end of one of the his most vitriolic Twitter attacks — in one tweet, he even referred to her as a “dog,” an ugly and dehumanizing epithet against a woman and one of the few African-Americans to serve on his staff.

White House press secretary Sarah Sanders suggested Tuesday that Trump’s counter-offensive would continue while Manigault Newman is in the news. Trump fights fire with fire, she said.

Manigault Newman alleged he used the n-word during a taping of “The Apprentice.” Trump has denied that, but the whole ordeal led to an awkward exchange Tuesday, in which Sanders couldn’t guarantee the President had never used the n-word.

While Manigault Newman has no proof he ever said it, for other allegations denied by White House staffers in the book she has later provided tapes of conversations, which has led staffers to wonder what other recordings she might have in her archive.

There are caveats aplenty for the distinction that Manigault Newman is the first former staffer turned antagonist.

You don’t hear a peep from the likes of Hope Hicks, who left under a cloud, or Sean Spicer and Reince Priebus, who were so visible early on.

Perhaps these and others have non-disclosure agreements in the same vein as the one Trump says Manigault Newman signed.

While CNN has not seen the specific agreement Omarosa signed, it has obtained a copy of the non-disclosure agreement sent to other 2016 campaign staff. It includes language that signees must not “demean or disparage … Mr. Trump … (or) any Family Member.” By signing, they also agree to binding arbitration. It notes that the Trump campaign has the right to take them to court.

It is certainly true that some former White House (Michael Flynn) and campaign (Rick Gates and George Papadopoulos) staffers seem to have have turned on Trump, and perhaps even in a more damaging way than Manigault Newman: They’re cooperating with special counsel Robert Mueller. We saw how ugly that could get when Gates spilled his former boss Paul Manafort’s secrets in federal court last week.

And the imagination runs wild with what conversations Michael Cohen, the President’s former fixer and lawyer, has had with authorities. He’s clearly turned on Trump since he gave CNN audio of a secretly taped phone conversation.

But Cohen is not out on cable TV slashing and burning at Trump. His betrayal, if that’s what it is, seems a little less whole-hearted.

And Trump, though he’s said to feel betrayed by Cohen, has not taken his frustrations public.

Flynn, similarly, hasn’t said as much as a mean-spirited word about Trump in public. His son still regularly chimes in to support Trump on social media.

That’s why there are so many people who wonder aloud if Trump is telegraphing that he’ll pardon people prosecuted by Mueller with his very political pardons of people like Scooter Libby.

Another spectacular White House flameout was the 10-day tenure of Anthony Scaramucci. Sure, he’ll criticize Trump obliquely or disagree with a decision here or there, but he’s turned his post-White House time to being a sort of White House emissary on TV.

Steve Bannon, like Manigault Newman, was fired by White House chief of staff John Kelly. And Bannon ran seriously afoul of Trump by steering his former boss toward the wrong horse in an Alabama special election and also with what seemed to be thinly veiled shots in Fire and Fury: Inside the Trump White House, the book by Michael Wolff.

But Bannon, though disavowed, is still very much on Team Trump. He’s a big backer of the President’s trade policies and his efforts to remake the Western world order.

That’s a very different thing than what Omarosa is doing, which is essentially becoming an enemy of the White House.

And clearly that public breach of loyalty has rubbed Trump in a way no other former staffer’s departure has.

Early in his career, Trump was asked for the “key things” a boss should look for when hiring someone and building a team.