I'm not sure what you're doing...flying WestJet YYZ-YYC then flying AC YYC-YVR? I can't imagine why you'd do that but...you won't need to leave airside unless you have a bag. You won't be able to get your bag tagged all the way through. If you've checked in for both flights and have boarding passes and no bag. You should be able to just walk from one gate to the other without issue.