He said heads will roll if he finds wrongdoing by security forces.

他称如果发现安全部队人员有违法行为，他们将受到严惩。

We'll find out who is responsible and heads will roll.

我们会找出谁该对此负责，然后付出代价，人头落地。

If we can figure out who this is, a very big head will roll.

如果我们能找出那个人，一个大人物就要滚蛋了。

There's a lot riding on this: if you get it wrong, heads— well, your head— will quite literally roll.

这有很多好处：如果你弄错了，脑袋——好吧，你的脑袋——真的会翻滚。

The expression " heads will roll" or " someone's head is going to roll" (roll) means someone will be punished for this;someone is going to get into trouble for this, perhaps even fired from their job – lose their job.

“heads will roll” 或“someone's head is going to roll” （roll）表达的意思是某人将为此受到惩罚； 某人将为此惹上麻烦，甚至可能被解雇——失去工作。