St. Paul's Cathedral has been transformed into a weapon of mass destruction.
Katherine stands outside watching as MEDUSA emerges from the top of the cathedral. The rain washes off the Guild-mark she'd painted on her forehead as a disguise, which exposes her as an imposter.
Taking a page from Tom's book of escape, Katherine runs. She runs so far away. Until she sees Chudleigh Pomeroy of the Historian's Guild. He helps her escape.
When Katherine and Chudleigh are far from the cathedral, MEDUSA ignites. "A snarling, spitting cat-o'-nine tails lashing out to lick at the upperworks of Panzerstadt-Bayreuth" (23.43).
And BOOM—it's gone.
Katherine expects all of London's citizens to scream in horror, "but no; they were cheering, cheering, cheering" (23.46).