Many of the teens at an antigun rally Wednesday afternoon at Copley Square had practiced drills at their respective schools to prepare for armed intruders. One speaker at the event had lived through an infamous attack.

“Five years ago at Virginia Tech, sitting in my French class, I went through hell, I barely survived,” said Colin Goddard, 27, who was shot four times during the deadliest school shooting in US history, an attack that killed 33 people.