Besides meaning "receive," "become," and (for casual
conversation) "understand," get can also mean answer
or respond to a ringing phone or someone who's
at the door.
Examples:
The phone's ringing, but I can't get it just now. Can you?
I hear the doorbell. Can you get it?
There's someone knocking on the front door, but I'm not
going to get it. I think it's a salesman.