A long time followed in which he considered the notion of following her, of interrogating her, perhaps even crippling whatever plans she had in motion by simply taking his brush back. It most likely would not take much more than a polite request, at that. But the doctor somehow did not register in his mind as simply another individual at this point. In his eyes, the capability she displayed eclipsed and predominated the whole of her sex. It was not that he felt any emotion akin to love for her - All emotions, and that one particularly, were abhorrent to his cold, precise, albeit imbalanced mind. As a lover he would have placed himself in a false position. He never spoke of the softer passions, save with a gibe and a sneer. They were admirable things for the observer, excellent for drawing the veil from men's motives and actions. But for the trained reasoner to admit such intrusions into his own delicate and finely adjusted temperament was to introduce a distracting factor which might throw a doubt upon all his mental results. Grit in a sensitive instrument, or a crack in one of his own high-power lenses, would not be more disturbing than a terribly strong emotion in a nature such as his. And yet there he stood, letting her walk away with a potentially damning possession.
It's just a brush.
He laid upon his side, and waited in the darkest corner for the sun to rise.
Only this, and nothing more...