Well, I'm no doctor ... but I watched on on TV...
"Tachycardia." That's what it's called when the heart goes into a series of very rapid, incomplete beats. Sort of like a seizure, or convulsions.
The heart is essentially electrically controlled. When a 'defibrillator' is used, many times it is to use the power of a big battery to overrule the chaotic impulses that, for whatever reason, the body is generating. A person in a state of tachycardia might very well show other twitching, feel numbness and tingling, etc.
The electrical 'net' of the body needs certain minerals to operate properly. That's why bananas (rich in potassium and magnesium) are so popular with distance runners. If your body runs out of these minerals .... tachycardia can result from even mild exertion.
None of this explains the reported 'shock' to the second victim.
Just wild guessing ... but you don't need an electrical shock to think you've felt one.
Blood tests will tell much. Once I transported the victim of a nearly fatal shock to the hospital. Upon arrival, they appeared perfectly normal ... and were treated in a perfunctory manner by the staff. Then the blood tests came back ... talk about a change of attitude! The tests confirmed that the guy had been waiting in line at Heavens' Gate ...
