Scott's story reminded me of an experience I had this week with a new apprentice.

He was on the ladder setting anchors with a hammerdrill. When he was finished I told him to, "Drop it by the cord". Well, he took me literally and dropped it. Fortunately, he caught it again about 1" from my nose!
It was my fault, I should have told him to "lower it", not drop it.
When you are supervising inexperienced help, make sure that your instructions are clear and unambiguous.
GJ