No, the park brake isn't also the emergency brake on a CJ.
Incidentally, a Sierra Eagle II will quite happly set off at quite a lick with the park brake set, should a happy chap carelessly set takeoff pwr, but sadly the wheels will not be a rollin'. Smoke - and quite possibly flames - would shortly ensue, if only from the CP's nostrils.
Finally, attempting to set the control locks on any Citation derivative whilst in motion would be a very, very silly thing to do.... nostrils, again.
(sotto) ... as would leaving a drawer open in an aircraft in a dark hangar, so the said CP skins his shin when climbing aboard early one morning.
