The detective instantly came to the conclusion that they had found the room they sought, for the brilliancy of the light told him that a big arc lamp, or other illuminating device of similar power, must be in use.
As he started toward the door, however, he became aware, for the first time, that there was a figure standing in the dimmer light of the hall, beyond the operating room, probably at the head of the first flight at the front.
More than that, the figure’s posture was a tense, listening one, and a white face was turned over its shoulder.
The form was that of a woman in a nurse’s garb. Undoubtedly their presence had been detected by Miss Rawlinson, who had evidently not seen fit to descend the stairs with the rest, but was waiting for their report as to the cause of the explosion.
When Nick first caught sight of her, she had seemed to be held spellbound by this unlooked-for invasion from the rear, but in a moment she recovered her self-possession.
“Help, Doctor Grantley—quick!” she called down the front stairs, in a high, shrill voice. “There are men in the house! It’s a trick!”
And as soon as she had shrieked her warning, instead of running to meet her friends, she turned and came flying along the hall toward the detectives.
Nick had thrown all caution to the winds as soon as he saw her looking at him. With a low-toned command to the others to follow him, he had leaped forward, and when the nurse started back to meet him—or, more likely, with the idea of keeping him out of the operating room if she could—he had almost reached the brightly lighted doorway.
“Stop! What are you doing here?” the woman demanded harshly. “You must not do——”
But, although the detective heard a clamor of alarm downstairs and the sounds of running feet, he ignored the nurse and sprang into the room.