what is up with the door lock system on this car...they seem to have a mind of their own.
This morning, while the car was running I manually pushed down the drivers side lock...and all the other locked (normal). As I shut the car off and got out, with keys in hand...the doors locked themselves after the drivers side was shut.

***Is there different scenerios that the doors can lock them selves?****

Also...I assume that if the key is left in the ignition...the doors shouldn't lock...or at least the drivers door...is this correct?

I don't want to get locked out with no key!!!

 

Designers like to play with the locks programming all the time. My VW for example locks all the doors, once the car reaches 8 MPH. Why not 7, or 10? Beats me.
The description of your system sounds logic and commons. You don't say what year it is? Newer model have the system re-programmable to few options.
I still remember sore arm I had, when I rented minivan that locked all the doors, when the key in the ignition was turned and required pushing special button to unlock it.
Being on vacations I had several moments, when after turning the ignition I wanted to get out to check something. BANG !

 

One more note. Later MB models have safety features, that if the door is not open in certain time after unlocking, it will lock the doors back.
Slow people seems to have lot of problems with it.
I never did.

 

it is a 1988