Sophia had hemolytic-uremic syndrome, caused by a specific bacteria--E. Coli O157:H7. It was the cause of the outbreak in the Pacific Northwest several years ago in undercooked hamburgers. Classically, but not always, in beef, it begins as a bloody diarrhea, and leads to a hemolytic anemia (red blood cells get destroyed in the bloodstream) and renal failure. In the girl, a normal creatinine should be about 1 (hers was 6.8) and a normal potassium is around 4 (hers was 7.3). That potassium can lead to cardiac arrhythmias and needs to be brought down right away. They gave her glucose and insulin, which helps push potassium into cells, and kayexalate, which prevents absorption of potassium from the gut. They also should give calcium gluconate, to stabilize the heart, but he didn't mention it. These measures can help a little, but dialysis ended up being needed.

Jack was the guy with a suspected heart attack following a fainting spell. He went into supraventricular tachycardia, which is a rapid, unstable heart rhythm. Adenosine is the treatment of choice, but none is available. Another IV drug that could be tried is Verapamil, but it doesn't work as quickly and in his case he probably was crashing too fast. Anna tried carotid sinus massage, which can stimulate the vagus nerve, which slows the heart down. They want to cardiovert, but the machine is out of energy. Finally, Carter sticks his head into a bucket of water. As mentioned, this leads to the diving reflex, which does work in slowing the heart down.