A few years ago I met a crazy BSAC diver (which is a redundant term) who told me of his first ever ice dive. He arrived at a local, frozen-over quarry and found someone who agreed to take him in as a newbie. The "experienced" ice diver simply jumped into the hole and went for a swim - no line of any sort, no compass bearing. Figuring that the experienced ice diver must be really good with underwater navigation based upon the many car wrecks, etc., in the quarry, the newbie also simply jumped in and kept up. When it came time to turn, the experienced ice diver looked about trying to spot the hole (which was, of course, now too far away to see). Then he freaked out, darting here and there, burning lots of air. Finally, he gave up and went limp at the ice surface. The newbie pulled out a knife and chiseled a hole through the ice (UK - not too thick) and inserted his snorkel through the hole - at least he wasn't going to run out of air. He did likewise for the experienced ice diver, who seemed to recover enough to panic again, and took off in another direction. Luckily, somehow both managed to find the exit hole. The experienced diver took off like a shot into his car and was not heard from again.