Saruman's Pits

[Morsul the Dark]

First off long time no see.

Secondly I've been listening to LOTR on tape, my job requires much driving. I've enjoyed getting back into LOTR been quite some time. Anyway, something caught my attention, Gandalf goes to Saruman then is put at the top of the tower(which seems a really odd lack of thought from Saruman) but Gandalf talks about seeing the first pits and evil works. How quickly did Saruman get those up and running? Wouldn't Gandalf have seen them on his way into Orthanc? I don't believe Gandalf was there too long.