|My buddy, finding Thunderbird Four
I distinctly remember having a second or so's brain space to think "Hmm. This isn't working out how I planned" in the middle of the "Well, shit, what now?" situation.
I solved the problem by dropping down a bit, stabilising, then ascending and swimming across to a nearby rock ledge at 6m, when I floated around doing a safety stop, clearing my mask and thinking baleful thoughts at my computer. And at my own stupidity. Luckily my buddy was fine, although he had his hands full shepherding some very new divers back to the exit point.
The second dive went much better, as myself and my buddy retraced our steps, and I practised a safe ascent, which went better. The only odd thing about that dive was that towards the end, my buddy signalled "I am cold, let's turn around" (he wears a wetsuit). We immediately turned round, but he suddenly paused, and picked up an object (I think a discarded metal ring from someone's dive kit) from the quarry floor. He then swam around for a while, looking for something, then carefully placed the object on the rock and swam off.
This is unusual behaviour, as most divers who have signalled "Cold" will start kicking with some speed once the end of the dive (and a nice cup of tea) is in site. I asked him about it later, and he commented "It just seemed really important to do that". We both pondered this, as this sort of fixation with completing a specific task, without thinking about the dive plan, is characteristic of nitrogen narcosis. However, we were only about 8m deep at the time, which is way too shallow for narcosis to kick in.
Was it exertion and cold causing a slight form of narcosis, or was it slight hypothermia? No way of knowing, but an issue to be aware of; that would be more of a problem if we were in the North Sea needing to get back to the ascent point, and then climb back into a boat.
Other than that, though, it was an interesting dive. And we found Thunderbird Four.