Another wet passenger footwell

[Stevers]

I've had a wet passenger footwell twice on my Pug 306 HDi GLX Estate and each time it was the little rubber pipe that loops into the A pillar just above the carpet.  The first time I LS-X'd the top of the pipe back into place and that fixed it for a while.  This time the damage to the rubber membrane was worse so I cut a couple of brass squares and soldered some telescoping brass tube into them so that I could sandwich the membrane between the plates and end up with a spigot to attach the pipe to.  I used a screw (in a little yellow rawlplug) to hold it while I glued it into place with black silicon gasket glue.   We've had plenty of rain in the last couple of days, and the well is still dry!
   

The pipe doesn't seem to be attached to anything on the other side of the membrane, so what on earth does this pipe do?  How can this repair actually work!

Thanks,

Steve