The page on converting your foreign license to a British Columbia one says:
Step 2: With two years' of non-learner driving experience, you'll need to take the Class 5 road test. Note: Bring another qualified driver with you for your test in case you don’t pass.
Why would that be necessary? I assume that even if I fail the test my license is still valid within Canada (up to 90 days) and therefore I can just drive away if I fail the examination.