I think in a high-stress situation like that, forgetting a detail like that is definitely possible.
I live in a house that's situated on a gravel road. The road does not have a name - it has a number.
I have NO CLUE what the neighboring gravel roads have for numbers. Furthermore, I don't really care. Now, I know that Zimmermann was a neighborhood watch guy and that he's supposed to care, but hell, I can't fault him for not knowing or forgetting (whichever it is) what the damned street name is.