What was found
WHILE CONFIGURING FOR CRUISE, SIC INADVERTENTLY PUSHED THE 'RIGHT ENGINE FIRE' SWITCH INSTEAD OF 'MACH HOLD". PIC TOOK THE CONTROLS, DECLARED AN EMERGENCY AND RETURNED TO MMPR. CREW SECURED THE ENGINE AND PERFORMED A SINGLE ENGINE LANDING WITHOUT FURTHER INCEDENT. MX C/A: INSPECTED AIRCRAFT FOR SAFETY, NO DEFECTS NOTED. INSPECTED ENGINES AND FIRE SUPPRESSION BOTTLES (2) FOUND INTACT, A/C OK FOR SERVICE.