Secondly: he would have fulfilled Driscoll's bombastic wish
`Further, from his point of view the choice of that bolt as a weapon was an ideal one. It had its significance. to begin with. And, though Driscoll had stolen the bolt secretly from his house, he didn't know that. Seeing the bolt on Driscoll's' desk, he naturally imagined that Driscoll had got it openly asked for it and that anybody in his own house would know it was in Driscoll's possession. Hence suspicion would be turned away from his own house! He couldn't have been expected to think that Driscoll had carefully concealed a theft of that trumpery souvenir, when it could have been had for the asking. Can you imagine what must have been his horror, then, when he found us suspecting his wife?'
The doctor took a long drink of whisky.
`You've got a better case than I' thought, my boy,' he said. `The Gentleman who pulls the cords must have been amused by this one. I am listening.'
`So, in his half-crazy brain, he evolves a new plan. He knew Driscoll was going to the Tower at one o'clock, to meet Dalrye, because he had heard it at breakfast. He didn't know his wife was going there, of course. His one idea was to get Driscoll alone. If Driscoll went to the Tower, he would be certain to be with Dalrye; and a murder might be devilish awkward.’
`You can see what he did. He took the hat and the bolt home with him, and left the house early; before one o'clock. He phoned Dalrye from a public box, imitated Driscoll's voice, and got Dalrye away. At one o'clock he was at the Tower. But Driscoll didn't appear; Driscoll was twenty minutes late….'
Hadley drank a mouthful of scalding coffee and set down the cup. He struck his fist into his palm. `Do you realize, man, that, if we look back over our times in this case, Driscoll must have walked into the Tower of London no more than a few minutes, or more likely a few seconds, before Laura Bitton did? Driscoll was late; she was early. And as soon as Driscoll got up to General Mason's rooms he looked out of the window and saw Laura Bitton by Traitors' Gate… In other words, Lester Bitton, lurking about for a suitable opportunity to kill Driscoll as soon as he could, saw both of them come in. He hadn't bargained on, her. There was to be a meeting, clearly. For fear of detection, he couldn't strike until it was over.
`He waited. As he had thought, a person of Driscoll's wild and restless nature, wouldn't sit cooped up' in General Mason's rooms. He would wander about, in any event. And he would certainly come down now, for his rendezvous with Laura…. Fell, when Driscoll came downstairs and met Laura at the rail, Bitton must have been concealed under the arch of the Bloody, Tower, watching them.'
The doctor was sitting back, one hand shading his eyes. The fire had grown to a fierce heat now. -
`He saw the interview, with what rage we can imagine. He heard Laura Bitton say she loved him..:. and then, a thing which must have crazed him by its perverse irony, he saw Driscoll leave her, hurriedly and almost contemptuously, and walk towards him under the arch of the Bloody Tower. Driscoll had done more than loved his wife; he had scorned his wife. And now Driscoll was walking towards him in the fog, and the crossbowbolt was ready in Bitton's hand.'