I am sure this is a known bug, but I can't find it anywhere by searching so I thought I'd post about it anyway. Event: When I pull a lever and I get "you can hear machinery" a section of wall disappears and a niche with a little goody (or even some phat loot) opens up. About half the time there's a glass wall in front of it, and you can't enter it. Workaround: find some stairs, go either up or down, come back and suddenly it's accessible. weird bug, that .....
My experience has been that you can navigate into those areas with the keyboard but not not the mouse. Don't know if this is the same bug or not.