99ML430. Got out of the vehicle for about a minute leaving the engine running.

When I tried to get back in all the doors were locked.

Shouldn't the front driver's door have unlocked when I opened it to get out of the vehicle? How could it have re-locked?

Was able to unlock with the spare - not using the buttons on the fob, which didn't work, but was able to use the actual key with some difficulty to turn the tumblers.

Thanks,
Al