How can you equate this with an unlawful arrest in the USA?
In Canada, the OP's case demonstrates a clear violation of the Charter and Criminal Code.
The case that you posted is an example of what police must do as part of their job. When police are faced with imminent danger, it is their job to shoot to kill. The officer isn't "getting away" with killing... it's part of his job to kill in such situations. Whereas your job description and mine never include death, theirs does. Cops are trained to use lethal force against bad people when those people present grievance bodily harm or death to the officer. They take an oath on it.
In the second case you're disregarding the internal investigations, the SIU investigations, the court verdicts, and the officer's decades-long record as an officer.
Do you not have any faith in the combination of the Canadian justice system, third party investigations, and documented performance records?
As a Canadian citizen, you are also protected by law in using force necessary to protect yourself from death. It just so happens that police find themselves around bad people more often than you do, because of their job description, so they are required to exercise that right more often than you.