this happens in my car when there is steady rain for a few days. i've come to the conclusion it is coming up from the wheel wells. if you look from the right angle through the slit in the left side floor of the trunk (guess this was intended for ventilation) you can see the road. i guess when driving the car the water can spray up there and enter the trunk. i get a wet spot in that very area everytime i do alot of driving in the rain. haven't bothered finding a fix since im upgrading soon to a mazda 6. guess this is poor ford design. no shock here
