Interesting things to note.
Both people are really keen to avoid being stabbed, this is very different body movement from the assaults on the unarmed that I've seen.
No feinting or complex actions
The bystanders don't give a crap.
Simple kitchen knife, no fancy brand name-anything. It'll still ruin your day.
Reverse grip is pretty popular (in my city anyway, this seems to be a very cultural and regional thing)
The verbal stage seems pretty long. Both guys might have been able to avoid the fight had they wanted to
The schoolboy was bady, badly injured, but you don't really see any "dramatic" hits