Rust Never Sleeps

After removing the rear doors, I decided to pull off the rear wings. The wings are fastened to the body shell with bolts along the top and sheet metal screws along the bottom. There are a couple of machine screws at the door frame. I soon realized there were two or three screws I wasn't able to reach from the boot. I puzzled over this for a few minutes and then started taking the interior apart. There had to be an access panel or door. Well I was half wrong. I pulled out the rear seat and the quarter trim panels and there was the wing. There isn't any other metal. The right wing was badly corroded. I had to use my cut off tool in several places. The left wing came off quickly, mostly because I knew what to do this time. I pulled up the carpet from the rear to help cut down on the smell, then stepped back for a minute to take a look at the car.
This is the left rear quarter where the wing attaches. Rust is from bad body work.
This is the right rear below the tail light. The view is from inside the boot looking out.

The rust is worse than my latest pessimistic prediction. This last picture is the left b-pillar viewed from the back of the car. It is rusted through at the back. So is the bottom of the partition. What? The right side of the car is usually worse. There was no collision damage here. So what caused this rust? My first thought was condensate water from the nearby AC unit. Along with broken glass there were some rags stuffed under the thing. It must have dripped all the time. But this was a lot of rust and the car only ran for 2 or 3 years. Water must have... No it didn't. I was looking at the broken glass and had completely forgotten that glass belonged to the driver's door window. Water came in through the window, pooled on the floor and caused serious damage. Now I was really worried. I decided to pull up the floor boards. If the frame was rusted through, the bomb might be a lost cause.
Taxis have wooden floors. They are designed to be removed during a PCO inspection. The frame is still in good condition. So are the areas where the body mounts onto the frame.

There were large piles of rust left on the ground after I cranked the bomb back into the garage.