Beagle,
Having used TCAS for 12 years, trust me. There is NO scenario where you would want to turn it off. With the lastest software its even used on the close parallel approaches now I think.
You get an RA you carry out the instructions and then simply say. fligiht xxx tcas climbing (or ) descending...
doesnt take long at all. Don't turn it off, dont ignore it or you will end up like the chaps that crashed over switzerland a year or two ago.
Cheers
Wino