There is a lot to read here! It's absolutely fascinating, but there are a couple of times information is repeated which could have been streamlined a little.
There are two floors that are recreated as offices of the time and they are quite atmospheric; it also wasn't very busy when we visited, which was towards the end of a Tuesday afternoon, so that added to the eeriness!
We underestimated how much there was to see and only left ourselves about 90 minutes. We could easily have stayed longer. We were there right up until closing time, but didn't feel pressured to get out by the staff at all.