As a hurdler, I spend a lot of time especially early in the season going over lower hurdles that are pretty close together. Add a little speed to the approach and you can practice a good fast rhythm. Keep adding speed without moving the hurdles farther apart though, and eventually there comes a point where it actually slows you down. No matter how good you are, you just can't run full speed at hurdles that are only, say, 20 feet apart. The point is that I think there is an ideal speed to approach the first hurdle and Grant Holloway may be just a little faster than that, which explains 1. why he looks at the end of races the way I feel in practice going over really tight hurdles with too much speed, 2. why he's untouchable indoor (in my experience if you go just a little too fast you can still hold it together for a few hurdles, before crowding becomes a problem), and 3. why his best performances tend to come in semi-finals and low-pressure races when he is relaxed.
In any case, still not a bad race for him at this point in the season, very respectable time, can't wait to see USAs and worlds.
And huge congrats to Devon Allen. What a performance. He showed up well-rested and ran his butt off. Hopefully he's still in this kind of shape come WCs!