That's how people get killed. The safest thing when confronted with an armed person trying to steal your car is let them. That's what insurance is for. The people who generally get killed in car jackings are the people who think their ninja skills will enable them to "get the drop on them".
If their goal is to kill you, that is a different matter but it is extremely uncommon for Canadians not involved in crime to have a killer pull a gun on them.
p.s. Thanks for acknowledging your inconsistencies, claiming guns should be allowed to defend your home then talking about carrying in your car.