Even if the bag was sealed, I don't think they could take it back once it left the delivery person's custody. That's usually how these operations work (but not sure about Uber Eats specifically). Too much risk of food tampering or other mischief.
Very likely. But he couldn't have gone more than a couple of minutes. I'm surprised I didn't hear him.
What I'm still unclear about is that someone nearby ordered the food, as I didn't answer immediately why didn't he ring hone to base or to the planned recipient for an address correction?