I just thought I'd post my experience with wet carpet and the solution I found.
It took a bit of investigative work but I worked out that, in my case, it was the sunroof drain holes being clogged. I rarely use the sunroof (and I've vowed to never buy another car with one) but that didn't matter as over the course of time (about ten years for me) dirt, dust, bits and pieces that are small enough to find their way into the drain holes can and will build up and eventually clog the pipe/hose that tracks down the car and behind the dash where it plugs into a hole to allow the water that has gotten in past the sunroof seals to drain out underneath the car, just behind each of the tyres.
From my research online this is a known problem with sunroofs and it is most often the front drain holes that get clogged. And, worse, the design of the Mondeo (and other Fords) drain hole plug means that some of the usual options like running a trimmer line wire through or high pressure air will not work and are even strictly not recommended by many as they may damage the Ford drain-plug (which, according to one person is actually based on a Volvo design).
These are the two best resources I used to fix my problem and, finally, resolve my wet carpet/floor problem. It took a whole day and pulling apart quite a few bits and pieces but it is the only known solution as the design is such that there is no other (known) way to access the drain hose in order to clear it up and get rid of the sludge that builds up over time.
I hope it's ok to post these links here.
This one is a good written description, with photos, of what to do
https://talkford.com/community/topic...sunroof/page-2
This one is a video
https://www.youtube.com/watch?v=qsIMQawXGI4
From now on I'll be checking on them more frequently and ensuring there hasn't been some blob of dirt or other object that may have landed in the sunroof cavity when opened that will eventually find its way into one or both of those drain holes.
I hope the above has been helpful to anyone who may experience similar wet carpet/floor issues as me.
Cheers