How do you understand  saving others  life

  This question is so hard , because in this time I never see who is die , and I can’t to save him , because I’m not a doctor , but， when a people  he  going to die soon ,  maybe I can help him , I can help him not to die , but if he has a sick , I can’t help him , i’ll think doctor help him better , and I can’t help him  don’t have trouble , I can make him have a good life , of course it’s after the die .