Von Rumpel stands in Etienne’s house. He’s been taking morphine for his pain, and wonders if his disease has been getting worse. He imagines that he can save his own life by finding the Sea of Flames. With this in mind, he staggers back to the model of the city—he’s sure the stone is there somewhere.
We see that von Rumpel is very near death, and so is especially desperate to find the diamond in time. He seems to transform into an even more monstrous figure the closer he gets to reaching Marie-Laure.