Hi Enter_Narne:

Get the training first. I agree with the experts that you should have the proper gear. You could put a pretty small rappel setup together. For example the NY fire department uses a small emergency setup called the Petzl ECO system.
http://www.firerescue1.com/fire-products...esaving-device/

This setup is basically a small Gri-gri and carabineer attached to 7.5mm Technora rope, of which I’ve seen in 25’ and 50’ packages.
There is another version called the Petzl Tactical EXO Eashook.
http://www.itstactical.com/2009/08/20/petzl-tactical-exo-eashook/

FYI - You might also be interested in watching and episode of the TV show Surviving Disaster: Surviving a Building Fire. It’s on Spike TV. In that episode Courtley twisted six strands of Ethernet cable together and repelled. A few different methods were shown included creating a Swiss seat (harness) and using a German technique to rappel without a harness.