(the termination of someone's employment (leaving them free to depart))
首をめぐらせば
When I look back upon the past―reflect on the past.
首をかがめて
with bowed head
to cut off one's head―behead one―decapitate one―(首にするの意味なら)―dismiss one―cashier one
首になる.
首をはねられた
I will answer for it with my life.