every man for himself everyone must take care of themselves and their own interests and safety.
☞ This expression has been used since medieval times, but from the mid 16th century onwards it has often been expanded to every man for himself and the devil take the hindmost or, less commonly, every man for himself and God for us all.
2012Bruce SchneierSchneier on Security Taken together, our findings show that human behaviour in life-and-death situations is best captured by the expression 'every man for himself'.