There were by standers in that video who did better. They weren't beat to a pulp and they didn't have to spend the night in the hospital. The person who video recorded the fight did better than the BJJ coach. That person not only didn't get their butt kick, but they were able to provide useful video for the police.
If you are thinking about that video in terms of who would have been able to fight better in that situation then you are missing the whole point.
1. You can't save everyone.
2. If Fighting is your only answer to how to address stuff like that , then you fail to understand the reality of the situation.
Bjj jumps into a fight where there are multiple attackers in an effort to save someone. End result. They beat his but and the person they were originally attacking. Double loss. In addition to that, he'll be lucky if he can remember what any of those people look like. Another loss.
Streetfights and conflicts on the street don't play by the same rules as fighting in the ring. I don't know how many times that has to be said in here. Because of that you can't go into those types of conflicts with the idea that you can fight your way out, or even with the idea that they won't turn on you. You also can't go into those situations where you think the only trouble you have to worry about is from those who are fighting the guy. Anyone in that crowd can be allies with the people doing the beating.
I'm pretty sure you'll see more video of BJJ and MMA being used in a street fight than Aikido being used in a street fight. There is a slim chance that an Aikido person would have engaged in the situation like the BJJ coach would have. I do kung fu and there's no way in the world I would have engaged like the BJJ coach did.
Every solution to trying to stop a fight in the street isn't choke hold, a punch, or a kick. Stopping a fight doesn't require that you get in between the 2 people fighting. In this case you had multiple people involved so the best thing you can do in this situation is not try to walk in the middle of it "Like you go street Credit."
I don't know anyone's youth background here, but the stuff that I had to deal with from the streets was always this done with the reality "Pick your conflicts carefully. Pick your fights with the understanding that you'll lose. All is fair game in a street fight." If you still want to fight after considering this then go for it. Just understand that's the reality of what you are about to enter into.