Feel like there's a typo here but I cannot for the life of me figure out what they *meant* to say
@stavvers @sophie I didn't know that it wasn't commonplace. I couldn't work out what was wrong when I first saw the original post.
Always understood it as meaning "for real", not as a test or training. You would be using a fire extinguisher "in anger" if you used it to put out a real fire that had started by accident, whether or not you were cross about it.