I initially took this to mean that the memory was so fragmentary that it took her a week to assemble it into any coherent form. Which would go a long way toward explaining why the last chapter felt so incomplete and unconnected to the chapter before it.
Then I read on and, nope, that memory wasn't fragmentary:
...She had listened as carefully as she could, day after day, while he ponderously declaimed and harangued, laying out a vast scheme of evil intention, concealed within the drivel of the rhymes.
So Satan's little absurdist theater routine literally took a whole week? While his followers just stood there like lumps and stared? Seriously, book, do they ever break to eat and sleep and poop during this ceremony? And what happened to the angelic armies that appeared at the end of chapter 30 and then were inexplicably gone in 31? Were they just standing there like lumps too this whole time? Why aren't they doing anything?
Satan suddenly looks upset and starts sniffing the air. (Hey, ever notice how everybody automatically ascribes regular mundane senses like smell, sight, touch, etc. to supernatural beings like Satan? Why does no one ever depict angels as having an entirely different set of senses too alien for us to comprehend?) He's apparently realized that there's someone hiding in the crowd "who was not one of Satan's own." Satan must be phenomenally unobservant if he's only just noticing this now after the weeks he's spent hanging out with these folks.
The high priests started rubbing against each other in a studied, formal sequence. They were watching for someone to make a mistake, someone who did not know the routine, the way to rub, the steps to take.
Ya know, if this group gets infiltrated often enough that they've developed a specific protocol to weed out moles, you'd think we'd have records of their existence from other sources than Michelle. Especially if Lucifer the Clueless routinely lets spies go unnoticed for days on end like this.
The cultists find the spy, who turns out to be one of the high priests. He gets stabbed in the back, the real high priests chuck his body into the fire, everybody's happy. Well, except for Michelle, who freaks out so hard she starts trying to dig her way to freedom through the dirt floor. (Predictably, Satan kicks the dirt back into the hole while she digs like that one asshole kid on the beach who goes around knocking down everyone's sandcastle.)
The fire was growing bigger. As [Michelle] watched, the flames parted around a blazing chasm. From deep within, she could hear childish voices, the crying of infants:
"Mommy! Mommy! Help!" a little voice called. There was the sound of running footsteps. A woman rushed up and pushed her way through to the center.
"Mommy! Mommy!" The small voice was full of fright.
"My baby!" the woman cried. "I've got to get my baby!" The fire grew higher and the black hole wider. Satan laughed.
Are you not even listening to the overused Admiral Ackbar meme, lady?
The woman ran over to the black hole and reached down. As she fell, there was a scream, an undulating howl. It stopped abruptly. And that was all.
Satan laughed again.
People will do anything for a child.
They will kill and steal and run wild,
Fall into my pit.
He slammed his tail on the ground. It was like a thunderclap. The hole closed up.
So, book, are you going to use this incident to explain my long-standing question of why the Satanists don't use their own children for these rituals? Is it because even they, the evilest of the evil, feel love and attachment to their kids, and therefore wrangling reluctant strangers' children who weren't brought up in their ways is worth it to them, because it means their own offspring won't suffer? Are you going to *gasp* humanize your villains a little?
Nope. This nameless Satanist lady who cares about her kid is just another big-lipped alligator moment in a book that's already chock-full of them, and we motor right on into the next bit of the ritual.
The cultists start bringing loads of bones into the room. A footnote assures us that most of this supply of bones comes from church reliquaries that the Satanists broke into. It's okay, Satanists, a lot of those relics were probably counterfeits anyway. Then Satan spreads some bones on the altar and goes through some sort of numerology-style rite with them, in a long, boring scene where Satan seems to ignore his followers completely and focus all his attention on his bone-counting for an uncomfortably long stretch of time. Say it with me: Why does anybody worship this guy again?
We do get a brief indication that the heavenly forces are still watching, though. Michelle starts pretending to be a puppy during the bone-counting ritual, and the archangel Michael essentially steps in to tell her to straighten up, fly right, and pay some goddamn attention. Nice.
We end with Michelle attempting to escape once more, getting herded back by the Satanists, and swiping a small bone that falls from the altar after she knocks into it. Good for her. Maybe if she tries really hard, she can keep this moment from becoming one of the complete non-sequitur vignettes that make up a good third of this chapter.