Cryptocaryon irritans (ich) has a phase where the protomont eventually attaches to a surface and begins its divisions of tomites. The surface can be sand, rock, side of the tank......
No, there is no reason to run anything in a QT tank, as its just being used as temporary housing. And if meds are used, it would kill the bacteria in the rock and sand anyways, so there would be no reason to have it in there.