Many things should never happen, but they do, and generally at times when they shouldn't. My own experience was due to a number of factors.
1) Sea conditions borderline for the night dive we were taken on. (Acknowledged by guide after, that sea conditions had worstened rapidly just after entry)
2) Zodiac returned to Livaboard, Buddy encountered equalisation issues at beginning of night drift.
3) Buddy and I surface on edge of reef with progressively larger swell, and drifting further from livaboard with currents, not particularly strong, but surf not helping.
4) Signal for assistance with torch, zodiac launches.
5) Am pulled onto zodiac, single egyptian in boat, torn between task of retreiving me from water and ensuring zodiac not washed up onto reef.
6) Buddy previously holding onto Rib while I boarded found it difficult to retain grip on pitching zodiac, and releases grip.
7) Buddy is not visible at this stage, wind and engine are all I can hear, I stand to look expecting buddy to be holding onto zodiac ropes, but no sign, realise that it's pitch black and sea surface making it difficult to see anything.
8) Zodiac driver turns to move away from reef, and return flapping diver (me, yelling for my mate) to liveaboard.
9) Engine starts, and my buddy remembers shoulder strobe and turns it on, we recover him.
This whole situation took place very quickly, I have no doubt that the guides knowing the currents were confident that there was no major problem.
My buddy was unflustered and quite calm, as he could see I was safe, could see where the boat was, and was quite happy that he could make it back to the liveaboard if necessary.
I on the other hand was flustered, couldn't see my buddy, had no understanding of the preparedness of the boat crew, or or their knowledge of the currents in the area, or expectations that my buddy would remember his strobe, had I been in my buddy's position I would probably have similarly been unphased.
It does happen, it didn't happen for long (couple of minutes) but enough to panic me (remaining calm when you feel that you will never see your best mate again does not come naturally).
We did learn from this, and will now not attempt a night dive without each carrying 2 x Glowsticks, a Strobe, SMB, Whistle and Torch. If nothing else we're well equipped to go to a Rave party afterwards.