How to get out of Nova Prospekt?

[Moorkh]

I've spent the past two hours trying out just about everything I can think of but I can't find an exit

Spoiler

after the big fight with an ant lion queen (the big ones). There is the room where the battle took place and its only exit leads to a section of the 'citadel' between the two walls, which start to move once you go beyond a certain point.

No way out?

 

[sk0aL]

Spoiler

After the citadel moves behind you, turn around and look to the right, a section of the wall is missing. Crouch jump up into it, or stack something if you can't reach it.

 

[Moorkh]

thanks, mate!

I can't believe how I could have overlooked that all this time - it is in fact a huge hole! I was sure I had checked out every last nook on both walls, but I guess I must have looked at the floor every time I went past it :O
Oh, well, shouldn't be playing the game in a single session, I guess, especially not if one is as slow as I - 27h and counting...