A crowd isn't expected.

Miss Cumberland's condition forbids it." Sweetwater nodded and slid in at the side door.
He found himself at once in a narrow hall, from the end of which opened a large room.

A few people were to be seen in this latter place, and his first instinct was to join them; but finding that a few minutes yet remained before the hour set for the services, he decided to improve them by a rapid glance about this hall, which, for certain reasons hardly as yet formulated in his own mind, had a peculiar interest for him.
The most important object within view, according to his present judgment, was the staircase which connected it with the floor above; but if you had asked his reason for this conclusion, he would not have told you, as Ranelagh might have done, that it was because it was the most direct and convenient approach to Carmel Cumberland's room.

His thoughts were far from this young girl, intimately connected as she was with this crime; which shows through what a blind maze he was insensibly working.

With his finger on the thread which had been put in his hand, he was feeling his way along inch by inch.