Ugh...i saw this once at a reptile rescue place I used to visit as a teen. It was a bit worse though. It was a hognose the decided it did not need to wrap the mouse. It grabbed it by the but and then just start swallowing. The mouse just squealed and squealed. The owner of the rescue said in the 30 years he kept and rescued reptiles he had never seen anything like it. I had no interest and sitting through that so I left. I came back the next week and the snake was fine. The owner said he eventually took a knife and severed the spine behind the brain on the mouse as it was struggling and the snake couldn't eat or kill it in its odd position and the squealing had already gone on for and hour. Really crazy.