boiling point, breaking point, clutch, crisis, crossroad(s), crunch, crunch time, Dunkirk, emergency, exigency, extremity, flash point, head, juncture, tinderbox, zero hour

contingency, possibilityclimax, turning pointhappening, landmark, milestonecondition, pass, situation, straitdeadlock, impasse, stalematecorner, fix, hole, hot water, jam, last ditch, pinch, predicament, scrape, spoteleventh hour, last minute

moment of truth, point of no return