I am pretty sure when you "go septic" it means that infection has spread throughout the bloodstream. I had a client friend of mine that swallowed a pork chop bone and evidently the sharp bone cause a tear in his lower intestinal lining. His wife told me that he had septic shock and thankfully was at the hospital already because of intense pain.
I may not have the details exactly perfect but it was something like that. As for how be swallowed a bone and didn't know it - evidently that happened because he and his wife said the doctors had seen it before.