I don't think I like the video. It's probably because it's one of the things that shouldn't have happened if the kids were being taught with a self-defense focus. Even for small kids I would be telling them things like: "O.K. guys keep your hands up so no one can hit your head." "Don't do this and don't do that." "Doing this will get you in trouble." "Doing this will make it easy for someone to put you on the ground and beat you in the face."
If you are relying on your friends to jump in and throw head kicks at the guy on the ground in some sort of effort to save you.
You would want them to be pretty quick.
Somewhere in their teaching, should have been the lesson of "This is how you approach your opponent." Clearly only one student got that memo and it wasn't the one that was laying on his back. Good news is that kid not only read the MEMO but he probably has it framed. Maybe one of those expensive wooden frames.