If you shut off the `Halt when empty` (or whatever it`s called) setting, you`ll probably get enough additional head passes to finish the job. There will be some ink remaining in the cartridge.
There is a spring loaded paddle within the cartridge that is held back by the ink bladder. When the volume of ink becomes low enough, there is not enough ink to hold the paddle back and a small `finger` connected to the paddle protrudes from the cartridge which activates a micro switch in the printer, telling the printer that the cartridge needs replacement. Although the paddle activated the low ink switch, the cartridge will have some ink remaining.
I understand that some people save their empty cartridges and after gathering a bunch, they suck any remaining ink out with a syringe and inject the ink into another cartridge instead of letting the ink go to waste.
Mark