Agatha Christie (especially the post-Freudian era between the wars) had a fascination with psychology, not just of murderers, but of the victims and suspects too. Here's a general observation about gender:
"...He went straight home, he says, but evidence was called to show that he did not reach his farm until a quarter to seven, and, as I have mentioned, it is barely a mile away. It would not take a half an hour to get there. He forgot all about his gun, he declares. Not a very likely statement-- and yet--"
"And yet?" queried Mr. Quin.
"Well," said Mr. Satterthwaite slowly, "it's a possible one, isn't it? Counsel ridiculed the supposition, of course, but I think he was wrong. You see, I've known a good many young men, and these emotional scenes upset them very much-- especially the dark nervous type like Martin Wylde. Women, now, can go through a scene like that and feel positively better for it afterward, with all their wits about them. It acts like a safety valve for them, steadies their nerves down and all that. But I can see Martin Wylde going away with his head in a whirl., sick and miserable, and without a thought of the gun he had left leaning up against the wall."
A generalization, certainly, but it accords with my experience. Discharging worry and emotion seems to free women, but has an oppressive effect on men.
BTW, the editing in these cheap old Christie paperbacks is quite good. I suspect that she delivered a very clean copy and didn't like editors fussing much with her prose. And of course, she'd have the power to dictate the level and quality of editing she received! Would that we were all so fortunate.