Why was he in a hospital behind a steel door?

Behind a steel door, of course, until he has paid.

Before him sat the large steel door with its security features.

Then he went to the steel door and held it open.

I know they don't open the steel door to white faces.

Then a steel door was opened, and they could step out.

The office has a steel door and a television camera watching the outside.

Then she had a window cut into the office's steel door.

Finally he came to the single steel door that led to what had once been his security center.

Now they passed through a steel door and into the mountain itself.