point of no return
Boulwarism – "Take-it-or-leave-it" negotiating tactic
Bridge of No Return – Bridge between North Korea and South Korea, formerly used for prisoner exchanges
China's final warning – Russian idiom about a warning with no consequences
event horizon – Region in spacetime from which nothing can escape
Fail-safe – Design feature or practice
Hobson's choice – Free choice in which only one option is actually offered
Sunk cost – Cost that has already been incurred and cannot be recovered
ultimatum – Final demand backed up by a threat
window of opportunity – Period of time
https://en.wikipedia.org/wiki/Point_of_no_return