Meera Thakrar said she had just gotten off a Duck Tour with her son and was rushing to catch what she thought was the inbound train when they fell.
"I was just rushing, thinking, 'Oh, that's the train I'm boarding,' but that train was on the other platform, not the platform closest to me, and I just stepped on the track," said Thakrar.
Thakrar and her son plummeted in front of a station full of passengers, who sidled up to the edge in horror and disbelief.
At that moment they saw a heroic effort by one man who jumped into the pit to rescue the stunned mother and child.
"I was fully aware of the third rail, not worried about that," said Kris, who rescued the mother and child. "I saw her fall in. I didn't know she had a kid. Then I looked and there was a kid. I jumped, I picked the kid up and I handed him over 'cause when I turned there was so many hands I didn't know what was going on."
As the 36-year-old and her son limped around the house Thursday, she said she has a new lease on life.
"God bless them. My good luck is with them and I'm so thankful to them. They saved us. They were right there, they just didn't care if the trains were coming or what. We fell, and they jumped behind us," Thakrar said.
The video shows the two of them walking -- not realizing there is a deep pit filled with tracks between them and the train they believe is theirs.
"I don't want to see. I am horrified," said Thakrar.
What she doesn't want to see is the reality of what happened and what could have been; the terrifying moments relived by people who heard about it, but didn't see it, until now.
"Oh my God. My heart's beating," said a passenger after watching the surveillance video.
The mom's heart is still beating, too.
Thakrar said she and her son are lucky they didn't hit their heads or get more banged up.
"I will not be accessing any trains. I would rather pay the $25 parking in Boston. But I will not be getting on the subway," said Thakrar.