His survival instinct immediately took over, allowing him to react without conscious thought during the emergency.

instinct 来自拉丁语 instinctus，意思是"冲动、本能"。这个词由前缀 in-（表示"向内"）和 stinguere（意为"刺激"）组成，合起来表示"内在的驱动力"。在现代英语中，instinct 指生物与生俱来的、不需要学习就能做出的反应或行为模式。