Bathroom GFCI outlet tripped after turning on my razor!
Yes, since your razor has two prongs, it cannot develop a ground fault by itself... a ground fault requires a third path.  Indeed, the path was through you, and indeed, it probably would have killed you.   And this is why we have GFCIs in bathrooms.  

Tearing it down was probably the triggering event.  My guess is also that the unit is repairable, but will need some careful and/or expert attention.  It sounds like you did find a problem, but shrugged it off because you want to shave.  You will not find another unit of this quality except maybe the $100+ Euro jobs.