In a life threatening situation, is it legal to kill people to ensure ones survival even if those people were not the cause of the predicament?

PS: Post originalmente publicado no Quora

In Brazil it may be legal, under certain circumstances.

Brazilian legal system has borrowed the “Notstand” concept from german criminal law. Nevertheless, the division between Rechtfertigender Notstand (StGB §34) and Entschuldigender Notstand (StGB §35) is only present in Military Penal Code of 1969. On the other hand, Penal Code of 1940 treats both cases as “Rechtfertigeneder Notstand”.

In few words, the Rechtfertigender Notstand (Justifying emergency) implies that one must break some law to save a more important good (such killing a lion to save your own life). On the contrary, Entschuldigender Notstand (apologetic emergency) means that the interest save by the broken law isn’t so important.

The implications of such concepts are different in German and Brazilian systems and widely discussed throughout academy. Sincerely, I cannot summarize everything here.