It's my senselessness! ...

It's my fault that you've got your proof!" He spoke in a tone of acute distress.
"It was your duty to give it me," said Guerchard sternly; and he began to mount the steps.
"Shall I come with you?
I know where the handkerchief is," said the Duke quickly.
"No, thank you, your Grace," said Guerchard.

"I prefer to go alone." "You'd better let me help you," said the Duke.
"No, your Grace," said Guerchard firmly.
"I must really insist," said the Duke.
"No--no--no," said Guerchard vehemently, with stern decision.

"It's no use your insisting, your Grace; I prefer to go alone.

I shall only be gone a minute or two." "Just as you like," said the Duke stiffly.
The legs of Guerchard disappeared up the steps.