Ok I read half the posts here and had to jump straight to making a comment. So if this was mentioned in the second half I apologize.
It seems fairly safe to assume that Shallan is unraveling quickly. It also seems a safe bet that this is because she has not made as much progress with truths as she has with lies (I.e. Not being grounded enough in truths to have a solid lifeline back out of her "lies"). This seems the direction of her inner struggle for OB. And man... from the preview chapters I would never have expected that to have me worried like it does. Amazing work BS.
Her external goals that are already in place seem terribly daunting. However, she can fail those and most likely not lose herself, her sanity, or Pattern. Yeah... this all has me much more nervous than I would have expected.