A door opened behind him, and he tried to turn in response.

A door opened behind me, and I heard someone walking my way.

Another eight minutes later the other door opened, in the wall behind the glass.

She heard the door opening behind her, and the light was turned up.

But before she could do so, her eyes opened wide in response to something behind him.

He immediately opened fire from behind the cover he'd just created.

He heard a sound as the door opened quietly behind him.

A moment later, the door opened behind us and she entered.

It was the sound of the stone door opening behind me.

The door opened behind her, and the elderly man came out.