Breitbart put it down colorfully. (no link of course.) Emphasis mine.

“Corey was escorted out of the building,” a source close to the campaign told Breitbart News.

Lewandowski came to the meeting unaware that he had lost the support of the GOP presumptive nominee, the source said. At the meeting, attended by both senior campaign staff and members of the family, Trump reviewed different campaign metrics that were all faltering: cooperation with party leaders, fundraising, surrogate operations and most importantly the polls.

The campaign manager seemed to have run out of ideas. When the New York City developer asked Lewandowski what he would do to turn things around, the only thing he could come up with was for Trump to announce his pick for vice-president.

Pitching that as the solution sealed his fate, the source said. “The VP pick was the one piece of suspense that would make people tune into the convention—Corey wanted to give that away now? There was no way.”

When the time came for Trump to lower the axe, no one spoke up to defend Lewandowski.

couldn’t have happened to a nicer guy.