Dr. Adrienne Wald, a nursing program director at UMass Boston, said her group of 30 nursing students were at the finish line assisting race finishers when the bombs went off.
"They did what they were trained to do," said Wald. "Instead of running away, they ran to help."
She said her students assisted at least one person whose leg had been amputated.
"It was a gory, gruesome scene that my students shouldn't have seen at this point in their careers," said Wald. "Who could ever be prepared for this?"
"They just started bringing people in with no limbs," said runner Tim Davey, of Richmond, Va. He said he and his wife, Lisa, tried to keep their children's eyes shielded from the gruesome scene inside a medical tent that had been set up to care for fatigued runners, but "they saw a lot."
"They just kept filling up with more and more casualties," Lisa Davey said. "Most everybody was conscious. They were very dazed."