(Late summary, with a few memory holes, sorry.)
With the suspect absconded, the team searched the empty storefront where "Sean" had been holed up. There, behind a SANGUSH ("I Belong") glyph, was his computer, slagged via thermite. Careful investigation showed that it was hooked up to the antenna outside, so it could transmit and receive to/from somewhere else (no way to know where). There were also burnt paper scraps with marking reminiscent of glyphs.
Via a ridiculously effective combination of Leo analyzing the paper and Edgar sharing his taisher visions, they were able to recreate the glyph. Leo spent the next hour carefully tracing it and attempting to understand what it did. As far as he could tell, it instilled solipsism ("This world is not real") in the viewer. If this was disseminated nationally or worse, it could be enough to shock the Red Kings awake!
Edgar knew that a directed use of his Sandman Foresight might reveal what was going to happen, but he wasn't strong enough to pull that off. So he took drugs. A lot of them. Blue Fire, Mind Hype, Yellow Billies (to banish his FP), and more -- as he held the glyph and used extra effort plus the Visions of Clarity technique. He got the strong sense that the biggest danger involving this glyph would come from the central Chicago Police precinct. They called, and spoke with Detective Freeman about shutting down all APBs and posts to the wire . . . but then they barely heard a female voice telling him to hang up the phone and do what she said. Click.
They team raced to the police station, while Johnny did what he could to help Edgar deal with drug interactions. Once there, Dawn took overwatch while Sarah tried to sneak in, but Sarah was caught; when she told the cop that her friends dared her, he led her out explaining how important it was that she stay in school. Change of plans, Leo created a SANGUSH ("I belong") glyph and walked in with Luis, Sarah, and Rin, telling the cop at the door that it was Bring Your Daughter To Work Day. Now they're inside, Dawn is still on overwatch, and Johnny is monitoring Edgar for when the taisher comes down from the Billies.