Hiding under a Rock
That could be a possibility. The sills and the carpet on the inside the car seem dry but then it's vertical surface so it wouldn't be exposed to water for any extended period of time.your water ingress could be caused by a door.
Your door seals can be fine but have water passing the outside window seal which would not be a problem normally as the bottom of the door has drain holes but if you have wiring from a speaker or similar that has managed to touch the skin of the door it can flow down the wire and down the inner side of the door carcass where it will come out between the door and the interior panel.
I was having water problems in the back and that is what it turned out to be and its been dry since i tied down all the wiring.