The majority of electric shocks are painful and surprising, but not fatal. It takes a good electrical contact between two parts of your body between a live source and a return path to allow high current to flow through your body. By understanding electricity and how it flows in differing quantities through many paths of resistance you can avoid putting yourself at risk of a fatal shock.
The safety industry implies that all electrical equipment should be locked out and tagged out before working on it, but in reality that is not always possible, although definitely a better option in the case of easily identified faults.
Much of the current wall of "one size fits all" safety legislation has come about due to the rise of all-trade building and facilities maintenance companies and their use of unskilled labour for economy. They often do minimalist in-house training before making their new "experts" sign liability waivers to avoid any legal repercussions.
Electrocution is normally a result of high current flow through your body. The most common mode of death is fibrillation of the heart. Your heart is actually composed of a large group of muscles that all contract in sync to deliver blood around your body. If they are knocked out of sync by the flow of current causing involuntary contraction of a portion of the heart, then they may not be able to re-sync and the heart will then function incorrectly and fail to deliver blood around the body, resulting in the potential for death.
The best way to defibrillate the heart is to use an AED Automatic External Defibrillator. These have evolved from the big scary hospital machines to sophisticated, affordable and compact units that can openly be bought for home use online and used by people with no previous training in their use due to the full automation and spoken instructions.
A defibrillator is applied across the victims heart by the use of two external electrodes. It then uses very advanced digital signal processing to make one of three decisions. It will NOT attempt to shock a healthy heart or one that is showing no residual activity (flat-lining). If it detects a heart rhythm indicative of a heart in a fibrillated state then it will advise a shock, charge it's capacitor, tell people to stand clear and then authorise the user to press the button. The resultant pulse of high current causes the heart to contract into a known and synchronised state, whereupon externally applied compressions (CPR) can then be used to help establish synchronised beating again as the machine continues to monitor the situation and make further attempts if needed.
It's somewhat ironic that the defibrillator was first developed to try and curb the high fatality rate of linemen in the American power distribution industry. And that now they have evolved to the point they can affordably be put into their trucks as part of their medical kits, the majority still don't have them. This situation is made even more incredulous by the high fatality rate that is ongoing in that particular industry due to their routine work in the vicinity of live power lines. (Isn't this what their union is supposed to deal with?)