Just finishing up the next chapter of Luke and Stef, and there's a definite difference to Simon and Trudi.
For the 'Wilhelm siblings' - as good a name as any - the next chapter involves a bit of talking as well as some 'action', but with them the focus is always the creep forwards.
For the Professor and his students, his focus is always on double-talking himself into letting his students push the boundaries again and again and again.
So, for those reading both stories, Simon will continue his sophistry, whilst Luke and Stef will spend much of chapter 3 having a conversation about what they're doing, and coming up with some good 'reasons' for what (may) happen next, after which they just get on with it.
Of course, for Luke and Stef it's more complex than that, but they won't know that for a couple of (their) weeks until...[spoilers].
All of which means, Simon will be back, and chapter 3 of The Wilhelm Scream is on schedule for Sunday's release.
CH