Imagine there’s banging on your door. What you don’t realize is that the person on the other side of the door has a gun. For residents of a Vaughan condo building, just north of Toronto, it was a night that changed their lives forever in one of Canada’s worst mass shootings. Reporter Catherine McDonald covered the story back in 2022 and spoke with the only shooting victim who survived, along with her husband who fought off the gunman. She returns now to meet the first responders who helped save their lives.