Due to security risks, they had to activate the killswitch to shut down the entire system immediately.

killswitch 是由 kill（杀死、终止）和 switch（开关）组成的复合词，字面意思是"终止开关"。在技术领域特指紧急情况下能立即切断系统运行的装置或程序，用于防止更大的损害或风险。