No, the other captives have their hands behind their heads (FXStandSurUniv), they are not in any sort of loop. When the trigger fires, they stop standing like captives and join my group. Push up man joins my group as well, but carries on exercising. As soon as the trigger fires, he freezes for a bit and then goes back to doing pushups.
playmove null keeps him doing pressups regardless, so I guess it will have to be switchmove.