Your first insight to seeing the ML's design flaw: get it wet

You can run it through the car wash (heaven forbid you wash your Mercedes Benz). I did the car wash when I started getting serious about understanding the Mercedes designed-in flaw to ensure the ML will rust.  So: wash the car.
Now:
1. Open all doors and tailgate.
2. See the water in all the interior spaces (inside the car). Especially note that the release latch on the tailgate will be wet -- water is coming out of that mechanism.
3. Note Mercedes is so aware of this design flaw they have put weep holes in all the doors and that water runs out of them. After a car wash. Note that the weep holes are placed facing the inside so they are actually making the problem worse.

More to come.