Yes, their are speacel segments for that i know that Luke314pi has a model pack that contains a fake floor segment
FAKE FLOOR
This model is the size of a FPSC floor segment. You can remove the floor below it, and set up an event to make it crumble when the player walks over it, and they can fall into whatever horror you have in store for them next!
YOU CAN BUY THE PACK HERE
http://www.luke314pi.com/fpsc/11.html
Ok luke your welcome you just got FREE Advertising ...But the next one will cost you
oh keerby you could also use the false wall that comes with fpsc its in the sci fi entitys. just rotate the wall using the 1-6 keys
hope this helps
Puk13