@ "There are only, so far as I can see, two possibilities approaching a suicide bomber ..."
"There are only, so far as I can see, two possibilities approaching a suicide bomber. He can be dead before the bomb goes off, or dead after it.
"The only way of even securing the possibility of no bomb going off is to ensure he's dead. After all, it's not like he's going to say, "I was going to blow myself up, but they've shot me. Drat!" is it?
"I therefore conclude instant death is the only logical possible response by the authorities. How anyone can say this approach is logically flawed is obviously using a different form of logic to any of the forms I'm aware of. Optimistic logic perhaps?"
Can you put that in your will/final documents? It'll save your family some time in court, to make your stance known should you ever be SHOT DEAD because the police think you are someone you aren't?
Because, as you said, it is better for the police to not take the chances.