Do you know who John Stuart Mill is and do you agree with his "greater good" philosophy?
You said, "taking a human life is not an absolute, but relative to the situation." I say, "taking a human life is not an absolute, because the sanction may change." In other words, the act that determined the judgement of taking the life is still morally wrong. However, the sanction for the act may change.
Murder is morally wrong, but capital punishment may be tempered with mercy. So that, life imprisonment is the sanction rather than death.
I am not familiar with his philosophy.
As you say, taking a human life is not an absolute.
While murder is morally wrong, is war? They both take human lives.