Press The Transmitter Unlock Switch Once
WARNING: This page is about a different car, the 2006 Mitsubishi Montero. However, it is still accessible from the selected car via links, so may be relevant.
When the transmitter unlock switch is pressed once, the ETACS-ECU energizes its door unlock relay to operate the door lock actuator of the driver's door for 0.5 second thus causing only the driver's door to be unlocked.