Sentence structure whatsits

Okay, so I have to confess that sometimes Hornung's writing makes me go "??". I think it's partially that Raffles uses a lot of cricket slang, and that Bunny's narration tends to be kind of on the colloquial side, but sometimes I think I'm just not following it sentence-structure-wise. So I thought I'd ask my lovely f'listies for some help!

This is from the story "The Spoils of Sacrilege". I've put this under a cut in case you don't want to be spoiled, but it's not a very long bit. Just two sentences, and only spoilery in the general setup of the story.

( I don't follow! )