Yes, you definitely want to power it down.  How many wires are connected to it?  Are they mostly 22G / 4 conductor alarm wire?  Any pictures of the install?
One way you could do it is to use punch down blocks.  If all the wires route out of the panel in a common direction (bundled), you could number each wire and cut it, then  punch it down to a 66 block.  If you leave enough slack on the panel leads, you can then punch those panel leads down to another 66 block.  You could then run a single 100ft. 25 pair cable between the blocks instead of individual lines.  It will make it much easier to pull and route the cable and to re-attach the two blocks.