episode 7 - What happens if the skin fitting flap for Airmar DST810 fails? Sailboat life

A mini Episode 7. We have an Airmar DST810 and recently the inside of our boat became very wet when we removed it for cleaning while in the water. Video shows it working properly, and what happens if it does not work. with 0.7m of hydrostatic head, there is potential for 10,000 litres per hour to flood in if it isn't stopped. glad its not a skin fitting failing. Life onboard our sailboat.