The patients left. Im not touching the other questions.

Your left it's your heart, my left if it's mine.

Stimulating the vagus nerve can drop your heart rate quite a bit, sometimes enough to cause them to pass out. If someone's heart is weak or diseased and their vagus nerve is stimulated enough that their heart rate drops too low too fast, their heart might not be able to recover and they can just die. It's why a lot of old people die on the toilet, the act of pooping stimulates the nerve and boom they're gone (see Elvis).

Sticking a fork in an outlet is a great way to give yourself Ventricular Fibrilation which is just like Atrial Fibrilation except that the Ventricles, not the Atria, are quivering. And when the Ventricles are quivering they aren't pumping so no blood is moving out into your body and you have no pulse and you are dead.

Fun fact, AEDs and defibrillators don't shock asystole (flatline). They shock 2 rhythms, in hope of stopping the heart so that it might restart in a better rhythm (have you tried turning it off and back on again?) V-fib is one of the 2 rhythms. Ventricular tachycardia (V-tach) is the other. In V-tach your ventricles are beating very very fast. You can still be alive and still have a pulse in V-tach (or not), which is why they say never to apply an AED to someone who is still alive, because it could recognize the V-tach, shock them and kill them.