She then turned to her husband and professed her love. "I'm so sorry for everything that has ever happened," she says she told him, in case they didn't make it.
But medical help did come. A doctor helped cinch her wound and the couple was rushed by ambulance just over a mile to Boston Medical Center.
Haslet-Davis could still feel her left foot as she headed into surgery.
Then, for the first time, it all went black.
She awoke the next day, groggy and in pain, with her parents at her bedside.
"I said 'Mom, can you help me? I feel like my foot's falling asleep," she recalled.
"I realize now that that was phantom pain, because she looked at me and said 'Adrianne, you don't have a foot.'"
Surgeons had amputated her leg 5 inches below her left knee.
"I just lost it," she said. "That's really hard to hear."
Dancing, she explained, "is the one thing that I do, that when I do it I don't feel like I should be doing anything else."
Ballroom dancers tend to roll and pivot on the edges of their feet, using a series of muscles and tendons to achieve a balance and dexterity honed with years of practice.
"You can't recreate that in a prosthetic," she explained. "But maybe the technology..." she paused. "We'll see."
A week after the attacks, now propped up on a hospital bed with her leg wrapped in hot pink cloth and gauze, Haslet-Davis has plans to get back to teaching the students who have filled her room with flowers.
"Part of my life is being able to teach people how to (dance)."
Months of physical therapy likely lie ahead, though she's already picked out her first dance: the Viennese Waltz.
"(It's) one of the tougher ones, but it's fast and it's beautiful and it's a wonderful, wonderful dance."
But there are bouts of anger and frustration that accompany her optimism, as well as a cloudy haze brought on by a steady cocktail of painkillers.
"I have moments when I throw water bottles across the room and throw my walker and just get angry and mad that someone did this to me... and that I won't be able to be dance with the same movements that I had before," she said.
"Dressing takes longer and showers take longer, and I get angry."
For many marathon bombing victims, the ordeal is just beginning. There's the physical and emotional toll, as well as financial. Hospital bills will add up, physical therapy and counseling sessions will be additional costs, and lost wages could further add to the burden.