“They were appalled by what has happened since Charlottesville and yesterday was the tripwire,” said one member of the panel. Besides Trump’s comments about who was to blame in Charlottesville, Trump also criticized Wal-Mart CEO Doug McMillon for speaking out about Trump’s response.

McMillon had told employees in a memo Monday that Trump “missed a critical opportunity to help bring the country together” with his comments. But the CEO chose to remain on the president’s forum. Trump lashed out at McMillon on Tuesday and accused him of being “politicial.”

“There was also a real chill…when [Trump] was critical of Doug McMillon at Wal-Mart,” said one source.