In the terrifying moments after the Boston Marathon bombing that changed Roseann Sdoia's life forever, firefighter Mike Materia was right by her side holding her hand.
He helped comfort her as she was rushed to the hospital that day in 2013 after she suffered serious injuries that ultimately resulted in her right leg being amputated above the knee. Materia, 37, would then routinely come check on her progress during her recovery.
Their friendship soon blossomed to the point where he proposed on Dec. 4 during a trip to Nantucket, Massachusetts.
RELATED: Meet the Boston Marathon bombing survivors who will say 'thank you' with 3,000-mile journey
"I've said from the beginning for me, (the bombing) was a lot of bad at one time for a lot of good for the future," Sdoia, 48, told Adam Reiss of NBC News before participating in Wednesday's Empire State Building Run-Up in New York City.
The couple shared a special moment when they climbed all 1,576 steps of the Empire State Building together to raise money for the Challenged Athletes Foundation.
"I think that he's just so kind and caring, and he just is very endearing and has been so supportive of me,'' Sdoia said. "He hasn't told me that there's nothing I can do. When you have a situation as having your leg blown off a lot of things change for you personally, mentally, physically, and none of that has been an issue for him."
RELATED: Boston Marathon bombing survivor helps amputee, 5, run again
They were joined by a firefighter from Durham, North Carolina, as well as Sarah Reinersten, of the Challenged Athletes Foundation, whom Sdoia also credits in giving her a big lift in her recovery.
Materia, who declined an interview with NBC News, even donned his full firefighter gear to trek up the steps with her.
"I'm not sure what's worse, one leg or bunker gear,'' Sdoia joked.
Materia has been with her throughout her journey following the bombing, helping her pick out her prosthesis and taking her to appointments. Sdoia chronicles their relationship in her upcoming book, "Perfect Strangers: Friendship, Strength and Recovery after Boston's Worst Day," which will be released in March.
RELATED: A dying girl rescued a kitten — who then rescued her heartbroken family
"We just were able to bond over it at that time,'' she said. "I think we both realized what good people each person is. I just feel very confident and secure when he's around."
Sdoia had walked in a 5K race in 2014, but Wednesday marked her first major race since the bombing. She practiced by running up and down the 294 stairs at Boston's Bunker Hill Monument.
She sported a big grin as she made it up the final steps to the Empire State Building's observation deck to complete the race.
"It was definitely difficult, I won't lie,'' she said. "I think we pushed each other through."
Follow TODAY.com writer Scott Stump on Twitter.