In canada, the firearms safety course does not discuss any protocol during a self defense scenario.
The homeowner with a firearm will react according to what is reasonable in his fearful panicked untrained state of mind and his lawyer will have no problems defending his actions once fear for life is established.
It is not reasonable to expect an untrained firearms owner whose only experience is safe gun handling practises and duck hunting - it is nOT reasonable to expect him to behave like a seasoned police officer.
Hell, you are in a fools paradise if you expect all young police officers to behave like a seasoned police officer.
They should be trainin' them for the "quick draw", eh Pilgrim?