OK, back to the question: The cadet/trainee answered the question from an LE perspective, and we can only speculate what went though his mind when he answered the question. To be the devil's advocate for a moment, perhaps he had just learned about "anchoring" shots, to use the SAS term for it. This is something private citizens, and even most LEOs, will ever deal with, but the concept does exist, in truly extreme circumstances. I remember the Peruvian commandos who stormed that embassy a few years back, to rescue hostgages, were using anchoring shots. The journalists covering the story did not "get it," and wrote it up as if the commandos were executing the terrorists. I am not saying LEOs in the USA are being trained to use anchoring shots, but we are taught that an apparently unconscious person is still a potential threat.
I remember us using batons and flashlights to knock "contact" weapons out of the hands of an unconscious person, so the paramedics could start working on him. (He had a death grip on a knife and a large flashlight; the flashlight had been snatched from an officer moments before; the bad guy was shot by a backup officer.) Had that bad guy suddenly become reanimated, while still armed, he might well have been shot again. An apparently unconscious person that is still armed with a firearm is an even bigger threat. We are indeed trained to be READY to shoot them.
