I think the big takeaway from at last seeing the third floor shadows in action, and from the little bit we do know about the Great Grandfather, is just how much we still don't really know about what has been going on with the third floor - there's virtually unlimited room for huge plot twists there.
Even the Second Floor shadows and their equivalents living elsewhere on the island still have a lot of surprises up their sleeves, as can be seen by the unexpected firepower that Eileen can bring to bear - Edward, Eileen, and Gerald work together pretty strongly, and would be a tough team to beat, even with, say, all the first floor residents working together against them, and there are many shadow adults at this level that we haven't even seen, if I remember gist of the estimated numbers that wee given in an earlier chapter's extras: I seem to recall there were a LOT of "Second Floor" shadows!
But it's not really been very clear, until Dorothy routed Anthony's rebellion, exactly what the Third Floor shadows are capable of, except for the barest hint of what happened to Thomas after his plot was uncovered: his arm was severed by one of the Third Floor shadows, presumably Ryan! (The story is no stranger to violence, but the violence IS handled with enough strategic restraint and is usually kept just off-screen enough, that it's especially horrific when we actually see, say, what happened to Maggie, or to the Belle twins, or Anthony's father, or what Dorothy did to the rebels (or at least their copies.... It's absolutely more effective than more technically violent stories tend to be in shocking with violence!)
Ryan might be our first hint of just how powerful the Third Floor shadows really are: they're apparently arrogant enough to have been pulling their punches so far, but also volatile and undisciplined enough to get so rattled as to fly off the handle and overextend themselves when called out by unexpected opposition, because they aren't used to losing a fight - that can be a pretty dangerous combination, for both sides!
They also at least SEEM to be powerful enough to "beat the hell out" of the Great Grandfather, and to manipulate him.
But then, what do we know about their control of the Great Grandfather, and about the GGF himself? Is he really being controlled by them, or by something else? Or, is he simply going along with them until he can get off the island, because it's useful to do so, and their plots barely interest or affect him?
Something tells me Ryan seems just a little TOO sure of himself, and his strength compared to the Great Grandfather, and that sort of overconfidence doesn't seem to have ended well for anyone else in this story - I can't imagine it's going to end well for Ryan, either, even if Ryan manages to win this fight, put down Anthony's rebellion, resist whatever Kate can do against him, and resume the presumed "elder abuse" of the Great Grandfather: we know even less about the Great Grandfather than we knew about Ryan, Sophie, Dorothy, and Joseph, we have no idea how strong he really is compared to them, and since most of what we know abut him comes from the little bit that Ryan and Joseph think (or claim to think - we really have no good reason yet to believe anything Joseph has said!), that situation might not be as clear-cut as it seems right now!
Anyway, the chapter is as always much appreciated, and seeing Edward's group in action, at least for the first round of a tough fight to be continued, did not disappoint. Can't wait to see where this fight goes next!