Once outside, he heard a key turn in the lock of the door behind him.

The sound of a key in the lock came from outside.

A moment later she had put the key in the lock and the door was open.

They heard the sound of the key in the lock.

They close the door and I hear the key turn in the lock.

The three men heard the key turn in the lock from outside.

Last night I couldn't get the old key to work in the lock.

She turned the key in the lock and went inside.

All I have to do is try my key in the lock.

She heard the key turn in the lock and saw the door open.