some players argued against the death of the character morpheus as the matrix now provides an "emergency jack-out" upgrade for redpills, eliminating the permanent death that previous redpills experienced if killed within the matrix before the truce. this feature could save a redpill's life with no fatal injuries. it was later revealed that the assassin's bullets had contained a new form of code encryption, named a "kill code," which bypassed this technology. these kill codes are explained to be extremely difficult to produce and usually require a direct sample of the subject's residual self-image data, thus making them extremely rare and only used in the most extreme and specialist of circumstances. these codes were utilized later in the story as well, being the basis of function for the apothecary character and the subject of the oracle's plan to wound the oligarchy.