REM and Electron Volts are two completely different critters. EV is a measure of electrical energy not radiation such as gamma. Rem is radiation Equivalant Man. It is a conversion unit that measures the amount of damage to the human body which is different from electrical damage. There are several different types of radiation you can be exposed to.

Unless you are attached to a very large conductor EMP will not hurt you. Ionnizing radiation on the othere hand is when radiation passes through the body causing damage to the cells. LD 50/50 or the leathal dose where half the people exposed to it will die. Depending upon which study you read LD 50/50 is between 500 to 600 REM.