After once again thinking about this scene and @matriarchcomputer ‘s analysis I can confirm that the mirror that Solo watches Illya in is fully within Illya’s line of sight. If you watch the scene by only looking at the mirror you can see the shadow of Illya’s movements. So Illya knew full and well that the mirror was there and that Napoleon could clearly see him.
This further proves to me that Illya did NOT want to kill Solo, and that he was doing everything in his power to give Napoleon a chance to shoot him without completely disregarding orders. He didn’t pretend to be even slightly okay (which to a spy is like the biggest red flag ever), he moved extremely slowly even though he can chase down a car, and if you watch carefully he even moves just a bit to be more visible in the mirror. He’s basically shouting ‘Please turn and kill me before I have to kill you.’
Illya was prepared to die to give Napoleon a chance to live.