Russian roulette
(a) act of bravado in which a person holds to his head a revolver of which one (unknown) chamber contains a bullet, and pulls the trigger 俄羅斯輪盤賭(逞能冒險舉動, 用只裝一發子彈 的左輪手槍對準自己頭部扣動扳機)
play (at) Russian roulette 玩俄羅斯輪盤賭.
(b) (fig 比喻) any action or situation involving serious and unpredictable risks 嚴重而不可預測的冒險行動或情況.