He jumped at her, and she pulled the trigger

Back in the dining-room he cleared the remains of the supper from the table and went out of the room for a few minutes, returning with a small pad of paper, and she saw from the delicacy with which he handed each sheet that it was of the thinnest texture. Between each page he placed a carbon and began to write, printing the characters. There was only one word on each tiny sheet. When this was written he detached the leaves, putting them aside and using his watch as a paper-weight, and wrote another batch.
She watched him, fascinated, until he showed signs that he had completed his task. Then she lifted the little valise which she had at her side, put it on her knees, opened it and took out a book. It must have been instinct which made him raise his eyes to her.
"'A Friend in Need,'" he read. "By Stanford Beale--by Stanford Beale," he repeated, frowning. "I didn't know your husband wrote books?"
She made no reply. He turned back the cover and read the title page.
He turned another page or two, then stopped, for he had come to a place where the centre of the book had been cut right out. The leaves had been glued together to disguise this fact, and what was apparently a book was in reality a small box.
The little hand which held the Browning was firm and did not quiver.
"I don't think you are going to send your pigeons off this morning, doctor," she said. "Stand back from the table." She leant over and seized the little heap of papers and the watch. "I am going to shoot you," she said steadily, "if you refuse to do as I tell you; because if I don't shoot you, you will kill me."
His face had grown old and grey in the space of a few seconds. The white hands he raised were shaking. He tried to speak but only a hoarse murmur came. Then his face went blank. He stared at the pistol, then stretched out his hands slowly toward it.
He jumped at her, and she pulled the trigger, but nothing happened, and the next minute she was struggling in his arms. The man was hysterical with fear and relief and was giggling and cursing in the same breath. He wrenched the pistol from her hand and threw it on the table.
"You fool! You fool!" he shouted, "the safety-catch! You didn't put it down!"
She could have wept with anger and mortification. Beale had put the catch of the weapon at safety, not realizing that she did not understand the mechanism of it, and van Heerden in one lightning glance had seen his advantage.
"Now you suffer!" he said, as he flung her in a chair. "You shall suffer, I tell you! I will make an example of you. I will leave your husband something which he will not touch!"
He was shaking in every limb. He dashed to the door and bellowed "Bridgers!"
"Come, my friend," van Heerden shouted, "you shall have your wish. It is----"
He spun round. There were two men in the doorway, and the first of these was Beale.
"It's no use your shouting for Bridgers because Bridgers is on the way to the jug," said McNorton. "I have a warrant for you, van Heerden."
The doctor turned with a howl of rage, snatched up the pistol which lay on the table, and thumbed down the safety-catch.
Beale and McNorton fired together, so that it seemed like a single shot that thundered through the room. Van Heerden slid forward, and fell sprawling across the table.
It was the Friday morning, and Beale stepped briskly through the vestibule of the Ritz-Carlton, and declining the elevator went up the stairs two at a time. He burst into the room where Kitson and the girl were standing by the window.
"Wheat prices are tumbling down," he said, "the message worked."
"Thank Heaven for that!" said Kitson. "Then van Heerden's code message telling his gang to stop operations reached its destination!"