I found this:
to be an absolute godsend
when I was getting stuck, although be warned: it is a complete walkthrough
, so you may inadvertently read too far
That being said, it's the clearest and most thorough of the walkthroughs I looked at.
I'd give you advice for the level concerned, but - to be perfectly honest - I just can't remember
Try Mind-tricking the officers on your left as you go for the door? Maybe?
Anyway, hope that helps...