Well, it looks like that expectation that Trump would fire Deputy Attorney General Rod Rosenstein and replace him with Rachel Brand, Associate Attorney General, has hit a bit of a snag:

Rachel L. Brand, the No. 3 official at the Justice Department, plans to step down after nine months on the job as the country’s top law enforcement agency has been under attack by President Trump, according to two people briefed on her decision.

Ms. Brand’s profile had risen in part because she is next in the line of succession behind the deputy attorney general, Rod J. Rosenstein, who is overseeing the special counsel’s inquiry into Russian influence in the 2016 election. Mr. Trump, who has called the investigation a witch hunt, has considered firing Mr. Rosenstein.

[..]

Ms. Brand now oversees a wide swath of the Justice Department, including the civil division, the civil rights division and the antitrust division. She helped lead the department’s effort to extend a law that authorizes the National Security Agency’s warrantless surveillance program.

In an op-ed article in The Washington Post, Ms. Brand argued that the law “has been valuable and effective in protecting the nation’s security” and that law enforcement officers would be “at risk” without it. Congress voted to extend that law, Section 702 of the FISA Amendments Act, last month.

On Friday, Ms. Brand hosted a summit meeting at the Justice Department on human trafficking. At that event, Mr. Sessions thanked her for her “strong leadership as our third in command at the department.”

There's no official reporting on the reason for her departure, but clearly chaos and questionable tactics fall in the wake of how both the Trump White House and the Department of Justice do business. It's entirely possible that Brand has opted to take herself out of the line of fire of whatever "Saturday Night Massacre" Trump has planned as Mueller's investigation closes in.