The conflict there was micro versus macro. Feral's sacrifice meant individual people would be saved and specific problems fixed. To single out one small example, someone has kidney cancer, they can get a new kidney, but other people could and would develop kidney cancer in the future - a micro solution. Allison looks for macro solutions, the 'perfect answer' - she would want to develop a cure for kidney cancer so that no one ever needs a non-cancerous kidney again and Feral doesn't have to sacrifice to give them hers. Now extrapolate that to world hunger, rapists, whatever - Allison looks for sweeping macro solutions to this issues, regarding micro solutions as temporary palliatives rather than true answers.