How could a man hold a blade at another man's throat and never even change his expression?

He got a knife out of his belt and held it at our prisoner's throat.

What was I supposed to do when my brother held a sword at your throat?

"Not one sound," she ordered next, sword still held at his throat.

I needed only to hold the point of my dagger at his throat.

He holds a dull dark blade at the girl's throat.

Just as fast, his other hand produced a knife to hold at her throat.

Still clutching him with one arm, holding the other hand at his throat.

And, as the sun rises over this very room, I will hold my feast at her throat.

She held a dark blanket together at her throat.