As awful as this seems, this does make sense within the context Mr. Bobs was given. If the dog wakes up it will alert Mr. Purpermane or Held. Now obviously hurting someone's dog is only a notch below their child and will certainly have a cost. Also if it survives, it definitely will alert its owner.

@ sporf

Sure, would have been more cautions to strangle the dog instead of tossing it..

But Mr bobs was clearly instructed to not inflict high level of harm.