She was standing there looking at him with a worried expression on her face.

The guard was already up and about, with a worried expression on his face.

If you are in any doubt which one he is, look for the man with the worried expression.

As the minutes slowly passed, Tom's face took on a worried expression.

She put the paper down and looked up at him with a worried expression.

He left soon after breakfast, with a worried expression on his face.

He took notice of the worried expression on her face.

When he came back, there was a worried expression on his face.

She looked at him with a worried expression and made to pass.

No one had any answers, but from each person's worried expression, everyone knew time was running out.