The trivia item below may give away important plot points.
Dr. Boone, after giving cerebral spinal fluid for a cure, starts to seize. Walter calls for a syringe of TPA. Tissue Plasminogen Activator is a protease enzyme that triggers the breakdown of blood clots. It is a primary treatment for strokes caused by blood clots. At the time this episode was made the cost was around $2000 a dose.