You will use up your last spool of the color you are quilting with on the last pass. Since this is a donation quilt I finished up with a slightly different shade of burgundy rather than wait until I get back to town to purchase another spool of the original color.
The bobbin will run out with only inches left to quilt.
I did manage to finish it. I quilted with a loose meander. I sewed the binding to the back, turned it to the front and sewed it down with a zigzag stitch.