After four months of training to run 26.2 miles, Siobhan O’Keeffe wasn’t going to let a broken ankle at mile 8 stop her from completing the London Marathon. For 18 miles, 25-year-old O’Keeffe said she battled tears and pain to complete the race in 6 hours, 14 minutes.

“It started hurting after about four miles but it just got worse and worse,” O’Keeffe told SWNS. “I had to stop after eight miles. It felt bruised and really heavy, I thought it was sprained. I didn’t think it’d be possible to run on a broken ankle.”

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O’Keeffe stopped at a medic tent where her ankle was wrapped and she was reportedly advised to stop, but she said her adrenaline kicked in and “all I wanted to do was finish.” She changed her race strategy and had to walk a bit to complete the race, and ended up running with a pacer for a few miles.

“Running was just agony,” O’Keeffe, who had raised nearly $80,000 for charity with a co-worker, told SWNS. “I can’t explain how much it hurt. I joked with another runner that it felt as though I was running on a broken ankle.”

After crossing the finish line and collecting her medal, O’Keeffe celebrated her accomplishment with family and friends before heading to the emergency room the next morning. An X-ray showed an obvious break in her fibula bone.

“The orthopedic surgeon said he had no idea how I ran with it,” she told SWNS. “He said it was a trauma break. He couldn’t believe it.”

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O’Keeffe was casted and will be evaluated for potential surgery, but said the experience has left her with “unfinished business.”

“I did say never again when I finished but I’ll never say never,” she told SWNS.