Dude, what are you spouting? The lead runners in an 800m semi intentionally slowed down to impede the guy behind them? You're insane.
It's not the responsibility of the race leader(s) to stay out of the way of the people behind them on a straightway.
In a semi, if you're confident you're in, you shut down. In the 800m, people tie up in the last few meters all the time.
But I guess it's possible that they looked up at the jumbo torn and thought (simultaneously), "Oh, no! That UCLA kid is coming and he might qualify for the final! Let's slow so that he can't get through and Ryan Martin can sneak by us on the outside instead"