Electrocution could be used to kill, someone could decide he or she wants to die by slowly being ground up for burgermeat.
The skull could be opened and then the brain slowly being scooped out until the lights go off.
One girl could ask to be skinned alive and left to bleed out.
Then there is the possibility that someone volunteers to be meat for a wedding or birthday or anniversary. But has only a short time and needs to put on as much weight as possible over a short time. He or she could ask if Evelina places her in a forcefeeder. Till she reaches the requiered weight. Evelina says no and the girls take her as their science project. fullfilling the volunteers wish of beeing constantly forcefed and humiliated by them. (In geese forcefeeding produces extra large livers and those are considered delicacies in some parts of the world) He or she could die on a ruptured stomach in the end. Then Evelina guts and cleans her out and sends the meat to the party.