Steve Poloz is good at economics, but not always so good at finding the best metaphor.
Greg Quinn says "Bank of Canada Governor Stephen Poloz said his “controversial” decision to cut interest rates in January could be compared to life-saving surgery for the economy and any resulting increase in household debt should be viewed as a necessary side effect."
A better metaphor would use the old proverb "a stitch in time saves nine". (If you delay stitching a tear in your jeans, the tear will get bigger, and you will need even more stitches later.) If the Canadian economy did need a cut in interest rates in January, a delay would have weakened the economy more and more over time, requiring the eventual cut in interest rates to be even bigger.
So if there are bad side effects from cutting interest rates (if stitches are necessary but costly), that actually strengthens the argument for doing a stitch in time.
Of course, if you delay stitching the tear in your jeans forever, then your jeans will die. Which is where Steve's metaphor comes back to life.
We should learn from Sweden's Riksbank's recent mistake. It kept interest rates too high for too long, for fear that cutting rates would lead to increasing debt, which meant it eventually had to cut interest rates even lower than if it had done so in a timely fashion.
(I'm still not sure whether the Bank of Canada really did need to cut interest rates in January, but if you think you probably need to cut interest rates, you should cut now. "Let's wait and see if it gets worse" is not a good strategy. And this argument for a "stitch in time" works in reverse too, if you think that interest rates probably should be raised, but are worried about the side-effects.)