Drivers side door

Hi folks, Yesterday I had quite a peculiar ,only once in a lifetime so far ,and somewhat perplexing problem .On unlocking my car with the remote commander, all doors except the drivers doors could be opened. The funny thing was I opened all the windows with the remote and tried to open the drivers door from inside. But it remained securely locked.I tried this a few times with the remote (locking and unlocking) but no result. The drivers door just would not open from outside or inside.

Then I put the key into the door and unlocked it This opened the door. It has not malfunctioned since, but it leaves me with a niggling doubt as to what could have gone wrong? Imagine being stuck in the car win an emergency where you cannot open the door from inside Any suggestions ?