“I think it’s fine that all these young students have been so enthusiastic for her opponent and say, ‘It’s all good, just shoot every third person on Wall Street and everything will be fine,'” Clinton told a small afternoon audience in Washington Heights.

The throwaway line came towards the end of a wonky 30-minute presentation to a small band of Hillary Clinton supporters in a sunny courtyard of a hospital. The former president was standing in for his wife, who flew to California for a weekend campaign jaunt.

He devoted most of his speech to intricate details of his wife’s plans to alleviate student debt, incentivize cleaner energy sources and train more skilled workers for high-paying jobs. But, as he has in the past, Clinton couldn’t help himself from wandering into the spirited electoral battle between his wife and Sanders, who debated for the ninth time in Brooklyn Thursday night.

Clinton is clearly irritated by the perception that Sanders has won the high ground among Democratic primary voters in the battle over who is best equipped to stand up to powerful financial interests.

He heaped praise on the Dodd-Frank legislation that imposed regulatory reforms to lower risk across the U.S. financial system.

“The truth is there are 50,000 fewer people there today. That Dodd-Frank act is working,” Clinton said.

That was his coda to the dicey remark opining on the solutions of Sanders’ supporters.

[DECISION 2016: U.S. News Covers the Race to the White House]

Clinton was very likely being facetious, but he didn’t pause to suggest levity and there little reaction from inside the crowd. In a heated primary where surrogates have been under heightened scrutiny for their remarks, the former president must have known he was taking a risk.

Clinton also took umbrage with Sanders’ claim that his wife’s string of wins in southern primaries are less meaningful because they are full of conservatives.

“Not Florida. It’s one of the most diverse places in America. They just believe in the future and they know who will change it. Not North Carolina, one of the most diverse places in the country. They understand the threat of people who want to take away their voting rights and they do not believe that the president lost the Congress because he wasn’t left-wing enough,” Clinton charged.

Hillary Clinton leads Sanders by 17 percentage points ahead of Tuesday’s vote in New York’s Democratic primary, according to the latest NBC/Wall Street Journal/Marist poll.

But Bill Clinton urged supporters against complacency, noting that New York is the only large state in the country to hold a presidential primary with no other local elections on the ballot.

“It means it’s harder to increase awareness,” he said. “We are just this close to growing again together and we don’t want to blow it.”