I think this discussion is a bit academic.
In most cases one will propably cry "mayday" and in the usual places all effort will be made by ATC to avoid all situations in which an RA might be generated.
Our TCAS training states that most deviations commanded will be quite little regarding the altitude gain/loss, and the V/S asked for will not exceed one engine out performance.
However, when certifying the new system, I think they had to show the system will not ask for something you can't do, which they could not, so they need to ask you to switch off that part.
Fumbling with the TCAS selector should in my opinion occur only when everything else is settled and ATC will have vectored everybody els off by then.