(a matter) of lifeand death; of vital importance ❍ 我跑得快，抄小路逃了回来。他妈的，～！ (《茅盾文集》Ⅶ—220) …but I ran fast and came back by a short cut. Damn it!It was a close call!/这是他们自己～的大问题，我们不得不尽最后的忠告。(《毛泽东选集》734) It is a matter of life and death for them,and we feel obliged to give them this final piece of advice.
性命交关交（攸）xìnɡ mìnɡ jiāo ɡuān
交关；相关。事情关系到人的生命。形容事情很关键、非常重要。of vital importance, of life and death