Freight Dog:
I can’t see how you could’ve done that any differently. Impossible when someone’s acting like that. Suppose as you did, try best to be calm, protecting yourself from implication, closing the door and doing what’s reasonable to get out of the situation (impossible in your case as he was blocking you).
I was tempted to do what I once saw Jack Regan do on ‘The Sweeney’…kick the door and bang it on his head, but I thought better of it. 
I did have my steel toe boot on stand by, in case he tried to pull me out of the cab, but he saw I was deadly serious when I told him to get the ■■■■ off my door, and the situation then died down.
I must be mellowing as I’ve got a bit older.