That's why he dislikes going out when there are a lot of people bustling about the streets.

I don't suppose he'll be out long." She hoped with all her soul that Mr.Sleuth would be in very soon -- that he would be daunted by the now increasing gloom.
Somehow she did not feel she could sit still for very long.

She got up, and went over to the farthest window.
The fog had lifted, certainly.

She could see the lamp-lights on the other side of the Marylebone Road, glimmering redly; and shadowy figures were hurrying past, mostly making their way towards the Edgware Road, to see the Christmas shops.
At last to his wife's relief, Bunting got up too.

He went over to the cupboard where he kept his little store of books, and took one out.
"I think I'll read a bit," he said.