My $.02 . . . . . since I was one of the group that day
The current was going pretty good on the line for the first dive, but once we made it to the Grove, it wasn't bad. Yes, you needed to hang onto the line for the descent and ascent, but once we made it to the wreck, the current was manageable. The group discussed it after the first dive and everyone agreed that we wanted to do the second dive. The current wasn't much different on the second dive and once we made it to the superstructure it was manageable. I didn't stray more than a couple feet away from the wreck on the second dive, but I am sure that I would have felt the current more if I had.
It really wasn't that bad, you could see the sand coming in, but it wasn't so bad that you couldn't see anything. The sandstorm was because of an upwelling (I'm pretty sure that is the term the captain used), the current for the descent/ascent didn't seem to be much different than the first dive. Visibility went down quite a bit (15'-20'). Enough to be able see the wreck and explore some, but low enough to where you really had to keep track of where you were and where you left the mooring line. My buddy and I stayed very close for this dive.
It wasn't so bad that you had to hang on once you made it down. Like many wrecks, the structure was enough of a barrier to the current to allow us to move around without having to fight to stay with the structure. Would I have come more than a couple feet above the wreck - no way!
Can I say that the diver did everything perfect? -- nope. Should he have stayed on the line until he the got to the wreck? - yep. Was making a free ascent in current rather than run out of air looking for the mooring line a mistake? Hmmm . . . definitely dead or floating on the surface alive . . . . think I would have chosen alive. Not the best situation to be out in the ocean floating away from the boat, but given the alternative . . . . Once he was on the surface he did the right thing, signalling the boat, inflating his BC and dropping the weights. I can assure you though, he had a safety sausage for the next day's dives!