Elizabeth Warren's husband explains how their dog, Bailey, sent him to the ER

In the middle of the interview, Mann got stuck on a question: What was something he could share about his wife that the public didn't already know?

Suddenly, turning her attention towards the kitchen, Warren yelled out: "Oooh!" Bailey, the couple's 16-month-old golden retriever, had bounded into the sunroom, making a beeline for the senator and her husband.

"To the rescue! Bailey!" Mann joked.

"Good boy," Warren said.

Hours earlier, Mann and Bailey had opened the side door of their Cambridge home, letting CNN reporters inside for the couple's first joint interview of the campaign. Mann's left hand was in a cast.

As Mann explained it, Bailey had recently been roaming off-leash in the neighborhood. He started playing with another dog, but soon "the play stopped, and the other dog attacked him." Mann got between the two dogs, and his hand caught on Bailey's harness, resulting in a broken finger.

Mann, a professor at Harvard Law School, headed over to campus to teach a class before taking himself to the emergency room.

Later, when Warren joined Mann for the joint interview, she wanted to set the record straight: "Bailey got jumped."

"Let's be clear. Bailey was jumped by another dog," she said. "And Bruce went to Bailey's rescue."

Both Warren and Mann have long been dog people. As Warren writes in her autobiography, "A Fighting Chance," when she was teaching at the University of Pennsylvania years ago, a group of students surprised her with a golden retriever puppy on the last day of class.

In the course of their wide-ranging interview, Warren and Mann pointed to Bailey as one of the most important ways in which they have tried to keep a sense of calm this year as the Massachusetts senator has been running for President.

Their previous golden retriever, Otis, "had gotten Elizabeth through" her first Senate campaign in 2012, Mann said -- "just by being this big fluffy golden."

"Otis was the calm. You can do this. We'll get through this together," Warren said. "I would often brush Otis while I'd be on a phone call."

Otis died just days before Warren's Senate victory. It was a painful loss for the couple, and for years, they said, they couldn't fathom taking on everything that came with taking care of a dog again as Warren juggled her new job in Washington and Mann continued to teach at the law school.

But last summer, Mann saw an opening. One of their grandchildren was visiting, so he would be home in Cambridge for an extended period of time rather than commuting back and forth to Washington, DC. He seized the moment and brought Bailey home.

Now, as Warren runs for President, whenever she is home in Cambridge, the couple makes time to drive over to Fresh Pond with Bailey. A "really good day," Warren said, is when they can do the loop around the pond twice in one day.

Getting Bailey last year "probably made no sense at all," Warren said, but now, they "can't imagine life without him."

"And besides, there's really nothing better than a golden retriever puppy to create the illusion of normalcy," Mann said.