In reply to Philb1950:
It must be an Indicator Wall thing.
In 2007 we were sunbathing and lunching on the ledge just at the top of Tower Ridge and had a superb view of the action on Indicator Wall. A leader was near the summit but was calling down for slack, increasingly angrily. His second was below the overhang and we could see he had slack but the rope was jammed around icicles not far above him. Thinking he couldn't hear his leader we shouted relayed instructions to the second. Some time later he got the message, freed his rope and his leader summited. When the second started climbing his leader paid out all the rope, the second shouted "take in" to no effect. We went onto the plateau, found the leader and told him he needed to take in. He said, " I know. I am just teaching the ****** what slack is".
I somehow doubt they ever climbed together again.