A car driven by a 76-year-old patient smashed into a hospital entrance, killing two staff members including a doctor who witnesses said was trying to push people out of the way, authorities said Tuesday.

Jane Berghold said her brakes, which had recently been worked on, may have failed Monday afternoon when her car struck the entrance to Brocton Hospital's Radiation Therapy Unit.

"It was when I went to brake that the car just didn't stop," Berghold said.

She said she was diagnosed with breast cancer in April and was going to the radiation center for a consultation.

"I don't recall much of anything. It all happened too fast," she said. She was treated and released after the accident.

Dr. Mark Vasa, 58, the chief of radiation therapy, died at the scene. Witnesses say he was trying to get people out of the way when he was hit. Susan Plante, 60, the center's secretary, died Monday night at a Boston hospital, according to the Plymouth district attorney's office. Two other staff members were injured.

Police were investigating whether mechanical failure or driver error was to blame. Berghold was not charged.