Las Vegas(CNN) The Black Eyed Peas' "I Gotta Feeling" began to play -- Bill Clinton's cue to get off the stage.
But the former president, addressing a gathering of the Asian American Journalists Association here at the Caesar's Palace hotel, wouldn't budge, insisting over the music that he wanted to take one more question.
"Let me answer it real quick and I'll go," Clinton said. "They want me to go, I would stay."
The questioner identified himself as a Democrat who loved Clinton as president and is supporting his wife, Hillary Clinton, in the 2016 election. But, he wanted to know: Why should Americans trust the Democratic nominee when she lied about her emails?
"Wait a minute," Bill Clinton said. "It's not true."
And so began the ex-president's unexpected fiery defense of one of the biggest controversies dogging Hillary Clinton's White House bid.
"First of all, the FBI director said when he testified before Congress, he had to amend his previous day's statement that she had never received any emails that are classified. They saw two little notes with a 'C' on it," Clinton said. "This is the biggest load of bull I've ever heard."
Clinton went on to say that while the classification system of sensitive emails was "too complicated to explain to people," what is clear is that Clinton and her colleagues were never being careless with national security.
"Do you really believe there are 300 career diplomats because that's how many people were on these emails, all of whom were careless with national security? Do you believe that?" he said. "Forget about Hillary, forget about her. Is that conceivable?"
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Clinton pointed to the number of prominent Republican leaders -- particularly those in the national security arena -- who have endorsed Clinton in recent weeks, as a sign that she is the only person fit to run the country.
"There are people who spent their lifetimes advancing national security who believe she's the only person that you can trust," Clinton said.
The former secretary of state's use of a private email server at the State Department has complicated her campaign, particularly as she continues to battle questions from voters about her trustworthiness and honesty.
The FBI concluded this summer that it would not recommend charges against Clinton over the emails. But the agency's director, James Comey, said while he had no basis to believe Hillary Clinton had lied to the agency, she had been "extremely careless" in her use of the private email server.
Clinton set off a political firestorm recently when she insisted that Comey had said her answers to the American public regarding the emails were truthful.
She sought to clarify those remarks at a gathering of Hispanic and African-American journalists in Washington, D.C., last week, saying she may have "short-circuited" her answers. That acknowledgment set off Republicans and critics, including her GOP opponent, Donald Trump.
"Director Comey had said that my answers in my FBI interview were truthful. That really is the bottom line here," she said last week. "And I have said during the interview and in many other occasions over the past months that what I told the FBI, which he said was truthful, is consistent with what I have said publicly. I may have short-circuited and for what I will try to clarify."