The difference between being rained on (even a torrential down pour) and what happened here is that the water getting on your bike isn't under pressure and firing at it like a jet.My 10 sits out in the rain all day - an 8+ hour soak while at work. ( I live North of Seattle, WA). I would say at least 100 days a year for the last three years. It has NEVER failed to start! Guess I'm just lucky.
Let us all know just what the end result was. I heard of using DIELECTRIC grease for the wiring connectors. Never had a need, but you may want that glopped around your connectors in the future. Give it a Google.