The first time I saw someone choked unconscious it scared the crap out of me. And it was made worse by the fact that it was a friend of mine...
It was many years ago at a local tournament. My friend was winning his match but got caught in a sneaky gi choke. He was (and still is) a stubborn bastard, so he refused to tap and passed out. He might have been out for about 10 seconds before anyone realized what was going on. When the referee finally separated the two competitors, I could see my buddy lying flat on his back and he wasn't moving. From my position in the stands I couldn't even see if he was breathing.
But then it got even worse...
He started to snore REALLY loudly. We're talking horrible-keep-you-awake-from-the-next-room-sleep-apnea kind of snoring. Everyone at the tournament could hear it. Then, just to make things even more dramatic, he started convulsing a little bit, like he was having a small epileptic seizure.
Finally - to my infinite relief - he woke up, sat up and looked around sheepishly. Objectively he'd probably only been out for a total of 15 to 20 seconds (including the snoring and convulsing) but it sure seemed a lot longer than that to me at the time!
In fact this is a fairly normal sequence for someone who has been choked out. The snoring is normal. The mini-convulsions are to be expected. And they're going to be a bit light headed when they wake up.
Judo and BJJ coaches seem to be divided as to what to do if someone gets choked out. The most common approach is to stand around and wait for the person to wake up. This works just fine 99% of the time. There are traditional judo resuscitation techniques
(known as "kappo"). Kappo is an esoteric subject, and I don't know much about it. But I'll give you some guidance coming more from a western first aid point of view.
In first aid class I've been taught to roll unconscious people onto their side or into the 3/4 prone position (IMPORTANT: you only do this if you're sure that there's no neck or back injury).
Being on the side helps drain fluids from the mouth and prevents the tongue from blocking the airway. And there are some Judo coaches who agree that this is a good idea
I don't want to scare you with all this talk about unconscious people. Most accounts of chokes gone bad involve cops trying to restrain someone high on PCP by squeezing their neck with a billy club. Hopefully that's not happening at your club.
In fact, chokes
are fairly safe.
The Kodokan, which is the central organizing body for Judo, has conducted studies on the safety of chokes ("shimewaza"). The results are encouraging: Judoka have been choking each other for more than 100 years without any reported fatalities
Attacking the neck is part of submission grappling and BJJ. If you do this sport long enough then eventually someone will get choked out right in front of you.
Now you know what to expect when that happens!