Self Preservation
Well, do you think this a basic animal instinct? Or do we humans actually have it as well? Survive at any cost. Even willing to sacrifice others for your own survival? Is it wrong? Is it natural. Let's remove the kiddy gloves and discuss it. To stir the pot a little I'll say this statement.
"Self Preservation is stronger than Love. People care more about their own lives they will even sacrifice their loves ones"