MONTREAL - MONTREAL -- Nobody took Marc Lepine seriously at first, when he walked into a classroom at the Ecole polytechnique on Dec. 6, 1989, and interrupted an engineering student's presentation on heat transfer.

He stood there, in his threadbare parka, holding a 223-calibre Sturm-Ruger rifle. People stared, confused. One student asked him if he was playing a prank.

"Everybody thought it was just a bad joke until he fired his weapon," Rolando Rifiorati said softly as he cast his mind back 20 years to his last class of that semester.

"Then a kind of panic took over."

Rifiorati, who was a 24-year-old student at the Universite de Montreal's engineering school, was witnessing the start of what is still Canada's worst mass shooting ever, an event whose 20th anniversary will be marked in solemn ceremonies across Canada on Sunday.

Fourteen women died in Lepine's 20-minute war on "feminists" -- the people he blamed for ruining his life. When he killed himself at the end of his rampage, he had 60 bullets left.

The slain were: Genevieve Bergeron, Helene Colgan, Nathalie Croteau, Barbara Daigneault, Anne-Marie Edward, Maud Haviernick, Barbara Klucznik-Widajewicz, Maryse Laganiere, Maryse Leclair, Anne-Marie Lemay, Sonia Pelletier, Michele Richard, Annie St-Arneault and Annie Turcotte.

It never occurred to Rifiorati at the time that Lepine was targeting only women. He first thought he was after the men when he separated the males and females into two groups.

"He kind of rushed us out of the class because I guess he was in a hurry to do what he needed to do," Rifiorati recalled in an interview with The Canadian Press.

When Rifiorati and the other male students tumbled into the narrow corridor which led to a bank of photocopiers and a small lounge, he was stunned to see everything was normal outside the classroom. He expected more people with guns.

"The guys coming out of the class were screaming that this guy had a gun and then we started hearing gunshots." Moments later, the classroom door swung open.

"We saw him come out of the room and start shooting all over the place," said Rifiorati, recalling how he saw bullets smash into the concrete walls.

"We just ran for our lives."

Rifiorati knew six of the dead, including St-Arneault.

"She was a very jovial girl, very happy-go-lucky girl, laughing all the time," said her classmate, who became a mechanical engineer. "A very happy girl."

Thirteen people were wounded -- nine women and four men. Three of the wounded were in Rifiorati's class.

The slain women have achieved iconic status in Canada. Their names are read out every year in remembrance of a horror that should never be repeated. The names are engraved into plaques that are granite reminders of promising lives cut short.

But little is known about the survivors -- those who dodged bullets or who had flesh torn apart by them. Some of their names are recorded in dusty media archives and texts but most are known just to family and friends. They usually politely decline interviews.

Some of those who are publicly known have grim stories.

Some students and staff never stepped foot in the Polytechnique again. Sarto Blais, a graduate, hanged himself eight months after the massacre, saying in his suicide note he was torn apart by guilt that he didn't stop Lepine.

The following June, his parents also committed suicide, unable to cope with the loss of their only son.

Male students came in for criticism after the shootings. Some people even said they should have overpowered Lepine.

"We were engineering students," Rifiorati said. "None of us ever had military training. None of us had police training. None of us could have possibly have that kind of reaction.

"I don't think it's possible for university engineering students to have the reaction to actually jump on a guy who's shooting all over the place."

Indeed, school shootings were uncommon at that time. There had only been three in Canada at that point -- one each in Ottawa and Brampton, Ont., in 1975, and another in Winnipeg in 1978.

Rifiorati coped with his feelings about the Polytechnique tragedy by talking to people. He noted there is a strong sense of community among students at the school, which sits on the top of a mountain like an "oasis" on the Universite de Montreal campus.

"You talk about it when you can. It's easier to talk about it with people who actually went through it.

"You have to talk about it," he said, noting he had already dealt with devastating tragedy in his life, the loss of his older brother in a car accident a few years before. "You can't just keep it inside."

Those Polytechnique survivors who do talk in public are firm in their message: Do not weep for us. Never forget what happened on Dec. 6, 1989, but always remember what has happened since -- the fine work of the school and the eager graduates who went on to stand tall in their community and professions.

Diane Riopel was teaching engineering in 1989. She missed crossing paths with Lepine by a whisker, deciding to wrap up her day shortly after 5 p.m. and head home.

"When I look at the chronology of events, I went this way," she says, tracing a line on the desk in front of her with her finger.

"And he passed behind me," she says drawing a line behind what would have been her back.

"I was spared."

Riopel, who didn't personally know the slain students, remembers the palpable sadness that swirled around the school -- indeed the country -- after the shootings. Professors grappled with what to tell their students.

"I'll always remember the student who called me and said, `I'm not coming back.' He only had one semester to go before he became an engineer."

She says it's rare when someone learns she works at the Polytechnique that she isn't asked, "Were you there?"

But Riopel, who has worked tirelessly to attract more women engineers into the field, is firm that the tragedy doesn't define the school.

The massacre "is part of our history but it is not our only history," she said. "Now we talk about what we've done."

The school is a major player among engineering schools, she points out, and one of the best in the country. Thousands have graduated in the last two decades.

"It's an institution to be proud of," she says. "It has marked the history of our country."

The number of women enrolled in engineering has gone up slightly, but, like in other similar schools, not dramatically.

In the fall of 1989, there were 622 women in the Polytechnique's bachelor's program. Twenty years later, there were 804. Riopel, who has even addressed elementary schoolchildren on the benefits of a career in engineering, says there has been progress but acknowledges work still has to be done.

Heidi Rathjen feels the same way but this day she's not talking about engineering.

Rathjen, who went from being an engineering student to a tenacious advocate for the reform of Canada's gun laws, is rolling up her sleeves again to protect the controversial federal gun registry.

"I'm going to keep fighting," she said in an interview, insisting that gun registry costs are under control and it saves lives.

Twenty years ago, Rathjen was studying in a Polytechnique lounge when a pale-faced student burst in and yelled there was a man with a gun outside. She didn't understand what he was babbling about and she wasn't afraid -- until she heard shots.

There were more shots. Screams.

Rathjen and other students huddled in the room and tried to hide, turning off the lights. Only a fragile door with a flimsy lock stood between them and Lepine, whose weapon blasts sounded like "planks of wood hitting the floor."

Forty minutes later, police showed up and took Rathjen and the others to safety.

Looking back, Rathjen smiles slightly as she remembers one of her friends, who was among the 14 killed.

"We were in the same clubs, we went to classes and organized the student yearbook and things like that together," she said of Lemay. "She was a wonderful girl, a total sweetheart."

Rathjen, who now works for an anti-tobacco organization, says her advocacy helped her deal with the tragedy.

"One of the things I was fortunate enough to have the opportunity to do is to help out at the school and to work on something that I believed in that would help prevent similar tragedies.

"My involvement in gun control stems from the tragedy -- it's a normal reaction -- but I came to absolutely believe in it," said Rathjen, who now has a daughter.

"In fighting back in whichever way we can, we can't bring the victims back but we can work to make the system safer, to make it harder for an angry individual to commit the same kind of horrible crime. It was too easy for Marc Lepine to get his gun."

Riopel would like to see one other change as the world moves on 20 years after the Montreal Massacre.

She would like to never hear Lepine's name again.

"We have given him enough publicity. Out of respect for the victims, the killer should be completely anonymous."