That's the point of any ethical/moral discussions. Is self-defence a situation that does allow you to kill another person?

Does a mother who forgets to pull the hand break of the car and kills her son, should do jail time?

Does a police officer who shots and kills a person which is in a degraded mental state but threats his life, be accused of murdering?

Does a police officer who shoots a known murderer fugitive without following the standard procedure be prosecuted as a homicide?

See the point?