Can a slipped disc or herniated disk in your neck kill you?

No: A slipped disc or herniated disc can press on the spinal cord or a nerve but will not put enough pressure on the spinal cord to interfere with the respiratory function. You would need to have a significant neck injury in order to do enough damage to interfere with breathing.

Potentially: If you have enough cord compression above C3 or higher, or if you have an anatomical abnormality where the brain stem or cerebellar tonsils are partially outside of the skull. It's rare, but that is how some football players die on the field. That is also why some are adamantly against chiropractic neck adjustments.

It can't: Can't kill you but it can definitely cause weakness and numbness; sometimes severe dysfunction