I think if you read what I said in it's entirety and not take it of context you would find that I mentioned:fuji said:In the real world you lack the information to be sure that the person you've shot and killed is the bad guy. LEO will give you a rough time if:
a) The guy turns out to be an undercover cop performing his duties
b) What you thought was a gun wasn't
c) Especially if in b the "bad guy" turns out to be a neighbourhood kid
d) Especially if in b the "bad guy" turns out to be your kid
The problem with shooting someone who is not a clear, immediate threat to your well being is that you likely are operating in a state of fear with limited information and you may exagerrate the nature of the threat and imagine things that aren't there.
When you then surprise the intruder with a bullet in the face you may recognize that face as one of your own just as you squeeze the trigger beyond the point of no return.
Even if it does turn out to be a "bad guy" if what you thought was a gun turns out to be a flashlight you have just murdered someone who was only really guilty of the relatively minor crime of breaking and entering versus your much more serious crime of murder.
There are reasons why the law is what it is, they are good moral reasons. In this case the law has it correct.
a) door being breached
b) no place to retreat
You mention that "MAYBE' the guy has a flashlight - the law doesn't differentiate here. If you have a REASONABLE fear it doesn't matter, the act of smashing the door down would put Reasonable Fear on the table.
You also mentioned a undercover LEO. It is doubtful that they would smashing your door down unless they wanted your ass bad for something it is most likely you know why and it would be announced to you anyways.