It appears the original owner tried to seal leaks around the emergency window frame with silicon sealant. When he did this, he sealed the two window drains located on the bottom of the pop-out frame. During heavy rains, water would get past the bad seal and fill the bottom of the frame. Instead of the water draining outside, it would run inside and down the wall.
When we bought this Mirada last fall, I was able to negotiate a great deal because of water damage around the Emergency window.
The damage looked horrible but after close inspection, I knew it was mainly cosmetic.
Right after we took delivery, I cleaned the silicon sealant off the emergency window and made sure the drains were clear. Last weekend I finally got around to repairing the damage.
I removed the delaminated layers of the wall and glued a new piece of paneling over the original.
I re-seated and sealed the emergency window frame and also repaired the the pop-out window seal.
You can read a very detailed article with photos on my Mirada web site.
Repair interior wall lamination damage | 2001 Coachmen Mirada 300QB