One can train a dog to behave in a particular way.
As one can train a human to behave in a particular way.
Though it's behaviour will always be compared with human behaviour, by humans.
And a human's behavior will be compared with dog behavior, by dogs... and cats, and horses etc.. etc...
The dog will not make such comparisons.
He or she certainly will. If you whine like a dog, the dog will react as they would to another dog. If you slowly blink your eyes at a cat, the cat will react as if you are another cat.
All theory of other minds starts with oneself and it's no different for them. What's amazing is that the theory can evolve so we can understand those quite different from ourselves. They can't do that quite as well as us, but they can do it. Smiling in humans means happy, but to most predators baring teeth means aggression. Even our close cousins like chimps and gorillas don't take it well.
Dogs, cats, horses, and certainly the other great apes (with time) can learn what the expression really means.
It will simply respond appropriately, according to circumstance.
You're taking the immensely complex set of factors which produce behavior, you're smushing it into a black box, and then you're calling that "appropriate".
He will respond in accordance to his nature, nurture, and character. Which also perfectly describes how a human will respond.
His experiences tell him what to fear and love and what does or does not work. That combines with character traits like boldness, extroversion, neuroticism, etc... and this is all undergird by a foundation of instincts (many of them common to many species due to their ancient nature).
Some dogs are reliable brave and aggressive, and respond to threats with aggression almost always. Some are frozen in fear and indecision over something like walking over ice. They can overcome learned fears and acquire new ones. They can learn to tolerate things they once hated and learn to hate things they once loved.
So if a dog kills a person because of the circumstances in which it finds itself, then it has done nothing wrong.
I agree he may not realize he has done something wrong, but if there is any sense in these moral terms they have to mean something. A dog has values, and if he kills someone he considered part of his pack in a panic over a misconception then that is wrong by the standard of his values whether he realizes it or not. His emotions will follow his values and he will mourn, and if regret means emotional pain that changes behavior he may very well regret.
The onus of responsibility for the dogs actions will fall upon humans.
If a human child urinates on someone's lunch would the responsibility not fall on the parents?
There is a difference between "doing nothing wrong" and "not knowing you've done wrong".
Dogs, young children, and grown-ass-men (if they're indoctrinated) may honestly believe they've done nothing wrong. If you blame someone other than them, you're asserting a duty for someone to teach and regulate them.
I don't have to say anything about when teaching, regulating, and displaced responsibility are appropriate to tell you there is a difference between a stone falling on an innocent person and a dog killing an innocent person. A dog may be a thousand times less capable of perceiving a moral principle than a man but he has values. A stone has no values. You can't trust a stone, predicting interactions with a stone (or an ant or a tree) has nothing to do with a theory of another mind.
You can trust a dog, and it's not because a dog is three-laws safe. If a dog was a machine it wouldn't be trust.