The setter is being a bit unfair in giving " Barney" instead of "barney". The latter is an argument or "run in", then "to" is "closed" as in a door. "Closing" doesn't seem to be an match for the part of speech, though.
Thanks, Chrise. Agree the "run in", but not sure about the "to". Besides being wrong part of speech, the "just" in the clue is redundant if your explanation is correct. But you're probably right and it's just a sloppy clue!