So Veterinarians' euthanize dogs in the vast majority of cases...What happens in the rest of the cases? Does the BCSPCA know what happens in the rest of the cases, then?

To euthanize dogs infront of other dogs would cause them stress? I don't think you would call what happened to the 100 Howling Dogs euthanization. Let's see if that matches with this definition:

EUTHANASIA: 1. an easy or painless death. 2. mercy killing; the deliberate ending of life of a person or animal
suffering from a incurable disease.

The ending of these sled-dogs' lives was neither easy or painless and was not a mercy killing as these dogs were healthy. So let's call this was it really was. And that is a horrible, disgusting, cowardly act of a deranged maniac who should never be left in charge of the health of any dog. These dogs were innocent creatures who lived to please their master, no doubt running their guts out, and this is the thanks they got. At the very least they deserved a good end. This is a betrayal of the highest order.