Dr. Jill Stein Gets Personal: How a Health Scare Got Her Into Politics (VIDEO)

During the first part of our interview, Dr. Jill Stein talked about promoting the Green Party platform, doing push-ups in jail and fighting for local food. The former presidential candidate for the Green Party in 2012 seemed like she had always been fearless.

But growing up, Stein considered herself to be a passive, so-called good girl. She was a high school student who strived to be well-behaved and pleasant, never one to directly challenge ideas or situations. She preferred to be involved in the equal rights movement for women and people of color and support ending the Vietnam War in the 1960s from the sidelines, not as a leader.

"I had all these sort of good behaviors that were deeply ingrained," Stein said. "I didn't see myself as someone who was really going to get out and shake the tree."

That changed years later when Stein faced a life-threatening health scare at age 41. An MRI revealed she had lost circulation on the right side of her brain. She had a carotid artery dissection, a tear in the artery that allows blood to leak between and separate the three layers of the artery walls. The resulting bloodclot can lead to a stroke.

Stein, who did not recall what caused the dissection, needed immediate medical attention. Since there was a traffic jam, the medical professionals at her MRI recommended she take a shuttle bus instead of an ambulance to Massachusetts General Hospital to get there faster. Stein had to sit on the bus knowing she could die at any moment.

"I wanted to cry, but I was thinking, oh, you're not supposed to cry on the bus, and I had this revelation -- that doesn't matter," Stein said. "That's one of those rules that don't count under the circumstances. Any second, it could be over. You can cry on the bus."

Stein made a full recovery, but she was never the same when it came to how she wanted to run her life. She transitioned from trying to make change as a non-partisan educator and physician to a full-fledged advocate. Ten years later, she entered politics with the Green Party.

"[The health scare] was a life-changing transition for me," Stein said. "I felt like wow, I've been given this second life starting at the age of 41. So I know an awful lot now that I didn't know the first time around. I'm going to really act on that and do what I can do in the time I have."

In the second part of my interview with Stein, who celebrates her 63rd birthday on May 14, she reveals how her brush with death catapulted her into becoming an activist and, eventually, a leader in politics.