Portal 2 I'm stuck in this place, is this door s'posed to open?

[inuyasha]

http://i755.photobucket.com/albums/xx198/kRb9-/2015-01-31_00001.jpg

As the title states, I'm suck here, railings prevent me from going down, Cave Johnson said a few things, and now I feel like that door's supposed to open, here're the prominent things from the background to show you where I am.
http://i755.photobucket.com/albums/xx198/kRb9-/2015-01-31_00002.jpg

I'm so sorry this isn't much to go on, but I can't really tell much else.

[Psyren]

Watch a YT video of that specific level (there should be tons of P2 playthroughs out there) and you'll see what to do. It's been a long time since I played through P2 so I can't give more specific help than that, sorry.