My thought is it took some time for the water to settle to where it's not supposed to be. After the car sat for a while it probably trickled down and pooled in the bottom on an electrical container. My main worry would be the ECU and respondent connections. As all of these vehicles are getting on in age I'm seeing more people with wires that have just failed due to age and cyclic heating exposing connections to short out.
Has already been awarded the title "Destroyer of Sleep"