1998 Avalon alarm happens w/ driver door key

Hi- I acquired a 1998 Avalon w/ 146,000 miles.

The driver door lock motor is dead.

I do not have a remote for this car.

When opening the driver side front door manually with the key the alarm goes off and lights start flashing.

Any idea why that is happening and is there a way to stop that from happening? short of replacing the door lock solenoid?

Thank you.