What is shown outside of the elevator at the end of Portal 2?

Solution 1:

Here are the screenshots of the rooms you see on the elevator ride up to the surface at the end of Portal 2. Apologies beforehand as some of the screenshots are a little fuzzy, but the descriptions should help clarify any details that may be unclear.

A row of four turrets initially targeting the player who then go on to sing

Two turrets singing

Four partially assembled/defective turrets

Three turrets at 90 degree angles (apparently mis-assembled)

Four turrets staring at the Aperture Science Weighted Storage Cube

Four turrets surrounding another cube staring at the player

Eight turrets facing the player in two rows of four

Two turrets who appear to be behind a ruptured transportation tunnel (would explain the angle of the turret to the left) or possibly tangled in roots (see comments)

A large room filled with an assembly of turrets, in the spotlight is the 'tenor' turret and in the background is the oversized 'animal king' turret

Solution 2:

Viewing this in 720p should help you see what's going on: