"A block of steel"

AH, he had an idea! It was not his own, but for the moment he thought it was. He would leave the office himself and thus give her an opportunity to quit her work and shut herself up with the safe. But—(was his mind leaving him?) there was something to be done first. The way must be cleared for the man in hiding to enter that room before she did. How was this to be accomplished? A dozen suggestions had been given him by his confederate, but he had forgotten them all. He was in too great a whirl to think, yet he must think; some way must be found. Ah, he had it. Taking up the receiver at his side, he telephoned to a German friend to call him up in five minutes, giving him the number of the telephone in the farthest room. This he did in German, telling him it was a joke and that he was not to insist upon an answer. Then he waited. In five minutes this farther bell rang. Calling to Miss Lee, he asked her to answer for him, saying he was very busy. As she rose, he gave a preconcerted signal on the door of Mr. Beers's room. As she disappeared in the one beyond, the dapper figure of Johnson crossed the outer office and slipped into the one holding the safe. A minute later she was back reporting the message and getting instructions, but the one thing she had to fear had been done; the trap had been laid, and now for its victim!

It was not long before that victim responded to the call. On the departure of the manager from the room Grace Lee rose, and with a conscious look toward the two clerks, slipped across the floor to the open door of the safe room. Entering, she swung to the door, which closed with a snap; then, with just a moment of hesitation, in which she seemed to be trying to regain her breath, she passed quickly across to the safe and took up her stand before it. So directly and so quickly had she done this that she had not seen the slim, immovable figure drawn up against the wall at her right behind the projection of a large bookcase. Nor did any influence for good or evil cause her to turn after she had reached the safe. All her thoughts, all her hopes, all the dreams which she had cherished seemed to be concentrated in the blank, eyeless object which confronted her, impenetrable to all appearance—a block of steel without visible opening—an enigma among safes—the problem of all problems to every cracksman in town but one—which was about to be solved if one could judge from the thrill which now shook her, and in shaking her communicated the same excitement to the silent, breathless, determined man in her rear, watching her as the tiger watches the quarry, and with the same tiger spring latent in his eye. In a moment her secret would be out, and then——