My Tin Lizzie nicknamed The Beast, was having a problem with thread breaking. I had already checked it several times and went around one more time to thread it. Only, I did not turn off the stitch regulator and it moved and took a stitch. Something, not sure what, cut a small slice out of my finger. Bled a lot (not on the quilt) and throbbed for an hour.
Always turn off your stitching before grabbing for the needle.