"I ALSO SAID that the law of the country defines when a citizen is allowed to kill and when they're not, so please do NOT repeat the questions.
...
Also, some of the circumstances you've mentioned do really exist, yet people are still trying to suppress their own feelings in order to prevent harm. However, some countries still savage despite the advance they've made in technology."
That's an easy pass off. In a democracy you vote for the gov't, you get a say in what is legal and what isn't. So I'm asking what YOUR opinion is or what you think Islam says your opinion is? If you were writing the definition of what self-defense is which of those situations would you included and which would you exclude?
I have my own opinion and the answer isn't the same for every situation but I'm not going to list them here for you to base your answers on.
PS I thought of them off the top of my head based on news stories I've been interested in the past. Ethical debates are so much more interesting when applied to real situations don't you think?