Door Latch problems of the 2001 BMW 330

I have a 2001 BMW 330ci that I bought new. Recently the door locks started to fail intermittently. When they would fail, you would only be able to use the key to manually unlock the doors. However, if you were inside the vehicle, you would be trapped because the doors could not be opened manually no matter what you did from inside the car. You could power down the window and give your key to someone to use it to manually unlock the car from the outside. The dealer told me that the computer door lock control unit was defective and would cost $680 to replace it. I believe that for safety reasons you should always be able to escape your vehicle from inside even if the computer fails. Should this happen if there is a fire or if your end up in a the water you would never be able to get out of the car. You are trapped inside.