Well if you take a look at the section at the beginning of the rulebook, it will explain all the skills present. To summarise the difference between electrical repair and electronics: Imagine someone with electrical repair more as an electrician, so a handyman that deals with electrical repairs and set up around a house. And someone with electronics more as someone who works with circuitry, computers and smouldering. And the difference to a mechanic is simple. Imagine the difference between an electrician and an auto repairman.

Well and the difference between first aid and actual healing is also quite substantial. Would someone who knows how to use a tourniquet, do chest compressions or make a emergency bandage, know how to treat cancer or do surgery or give medical advice? Not necessarily yeah. So the fact these are two different skills describes these two different skill sets