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May 16, 2017, 2:58 AM UTC / Updated May 16, 2017, 6:33 AM UTC

The Trump administration, already in near-perpetual crisis management mode, scrambled again Monday night to respond to yet another explosive allegation.

This time it was reports that President Donald Trump had disclosed highly sensitive classified information to top Russian officials.

The face of the response was National Security Adviser H.R. McMaster, well-regarded as a steadying influence but facing his most visible — and most fraught — moment in this administration so far.

Minutes after The Washington Post broke the story, McMaster found himself in the wrong place at the wrong time: emerging from a West Wing doorway to stare down a hallway of restless reporters, stunned to see him at first and then expectant. He had come to brief them, they assumed.

Instead, McMaster backed away, smiling.

"This is the last place in the world I wanted to be," he said before retreating into the West Wing, ignoring questions.

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McMaster had inadvertently stepped into the center of the action, becoming the only senior staffer visible in the whirlwind hour after the story made headlines.

A senior communications aide had been seen not long before the story broke, looking rattled. When the story went live, White House Press Secretary Sean Spicer, Principal Deputy Press Secretary Sarah Huckabee Sanders and Communications Director Mike Dubke were in the West Wing — not their offices — as other members of the communications shop gathered for what could have been an unrelated meeting.

National Security Adviser H.R. McMaster speaks to reporters Monday outside the West Wing of the White House. Mark Wilson / Getty Images

Outside Spicer's office, the gaggle of reporters had grown from a few to 22.

A junior staffer asked reporters to clear out and head back to the briefing room, but nobody budged. One reporter was overheard on the phone saying: "I'm here at the White House. I was going to leave an hour ago."

At 6:24, an email announced the administration's new ambassador to the Bahamas.

Ten minutes later, another email arrived. This one included statements attributed to McMaster, his deputy for strategy, Dina Powell, and Secretary of State Rex Tillerson, declaring the Post's story to be "false" and denying that the president ever revealed intelligence sources or methods.

Six minutes later, Spicer made a hallway appearance, sending reporters scurrying back outside when he said McMaster would brief them on camera.

But McMaster's carefully crafted statement, a half-hour later, didn't deny what was being reported. The Post, after all, never said the president had revealed sources and methods — only classified information that could lead foreign intelligence agencies to zero in on those assets.

President Donald Trump greets Russian Foreign Minister Sergey Lavrov at the White House on May 10. Russian Foreign Ministry photo / AP

A smaller group of reporters began trickling back toward Spicer's office about 7:30 p.m. A reporter said he'd just seen Spicer, Dubke, Sanders and Trump's chief strategist, Steve Bannon, walking near the Cabinet Room. Another person heard yelling.

The handful of people lingering near the West Wing door quieted immediately, trying to listen in. Soon, the volume on the television in the press office was cranked up abnormally loud.

An aide who was walking by deflected an inquiry about the Post piece, saying: "I'm dealing with other dumpster fires."

Sanders then emerged from the West Wing, saying: "We're not answering any other questions right now, so you guys can clear this hallway."

Asked whether McMaster or anyone else would clarify matters, she repeated: "Tonight, we are not doing any other questions. At this moment."

What about Tuesday, the reporters asked — would McMaster still brief the media about the president's foreign trip, as previously planned?

Raising her voice to be heard over the din, Sanders replied: "Guys. I've said all we're going to say."