Unfortunately, instances of like this are not uncommon. I seem to remember that recently a young guy got knifed to death on a bus in Ottawa and none of the passengers came to his aid. In some cases people are afraid of retaliation from the thugs. Especially, when the thugs are usually out on bail in no time flat. This is not helped (in my view) by the government more or less outlawing a citizens right of self-defence. I also place some of the blame on the authorities. How many times have you heard of an incident somewhere in Canada and the police and/or politicians stand-up and say "Don't get involved. Let the professionals [police] handle the situation." You hear that enough times and when something does happen, no one does anything.
Like I said just my personal views.