Yes, Sue is still in residence but this would take a diversion to the Field Museum when time is of the essence, and it fits the circumstances given all modern vehicles are kaput, and the city is dark very like Dead Beat which it should remind him of.
Besides it provides a love interest for Ferrovax, which would be an interesting sub-plot.
Jim has said Sue would return, this would be the obvious point and conjuritis is obviously for something, perhaps Harry will sneeze out four bicycles. Besides Jim would just love the agony of Harry sneezing out a dinosaur and having to clear the ectoplasm from his sinus’s. Jim lives to hurt and embarrass Harry in new ways, his creations must suffer. The question is whether Harry is going to claim he did it on purpose or admit that it was an accident.
Note they went to the Marina in a rented car because Murphy’s feet don’t reach the pedals of the Munstermobile. So the rented car they travelled in would have been a bust.