He has also traveled a lot for racing. He and his teammate were all over the country many times since January. They've also raced a lot of fast races. NP was more calculated in their efforts
It's a startling thing to see from a high school workout, but I think it's also impossible to judge without seeing the full training plan. According to my watch its a 1:47-high with a rolling start. It's also well paced with no traffic and he's on the rail the whole way. You don't get a smoother more perfect setup than that.
What we do know is it's 5 days out from a 1500 race. When you're that fit, a single 800 race is pretty easy to recover from. In my opinion, a more traditional workout like 8x400 @mile pace would stay in your legs longer than an 800m time trial.
It should be noted that he ran extremely well (3:36) in that 1500 race 5 days later.
On the one hand he and his Crater teammates (Gorze, Kitchen) have been training at a high level since freshman year and his coach has modeled their outcomes on the Newbury Park program ()
On the other hand he has a lot of physical growth ahead of him. He's a small guy when standing on the starting line with other milers. He'll improve with size alone.
"He'll improve with size alone"? Improve in what? Running? Seb Coe raced at 5'9", 119lb. El Guerrouj was 5'9", 128lb.