He does not delay entering. He does however probably take one maybe two steps in which he could be "partially running out of bounds. I mean it is literally an OB's play where we make a pass to sideline top, he sprints to the corner for a pass and shot. By the time he catches it, he has already established himself and it's not running down the Baseline out of bounds and then stepping in.
I do appreciate the person who actually cited the rule book. However what rule book is that? I have looked up and down the NFHS rule book for 2016-17 and can't find this at all. I did find a few things back in 07-08 where it said if you go out of bounds legally, and delay coming back in to gain an advantage it's a T. However that says nothing about a throw-in and if you don't take your first step in bounds it's a technical.
Here's a link to the play.
https://app.krossover.com/r/2fog