The DPDS has departed.  The brood haven't established how they transport themselves yet.  I would bet on some kind of magic teleportation, or perhaps something along the lines of the Nidus Canal from Starcraft.  (basically, a biological subway system)  The DPDS is currently setting up defenses at the London base camp, while Frankie goes to investigate the weird energy signature, and just happens to run into Dorian.  I'm not quite sure how Dorian ended up in London or what precisely he was doing though.