From FEE.org:

The shooting that took place in Toronto (Canada) on Sunday was, in one way, similar to the aftermath of the terrorist attack in Paris on January 7, 2015. In the latter case, people took smartphone videos of fleeing terrorists shooting at policemen and killing an unarmed one. In Toronto, there were several powerless witnesses, and at least one person, apparently from an apartment overlooking the scene, videoed the killer as he was firing from the sidewalk below. In both cases, if a video taker had had a pistol instead of a smartphone, he could have engaged the killer, at least slowing him down, and saved lives or prevented serious bodily injuries.