His first shot clearly shows a standing position inside turn 2 or turn 4. The problem with that one, as I and others pointed out, was not necessarily a lack of positional access, but a lack of attention to the framing that his access afforded him. If you have access to the infield, which he clearly did, then the object should be, as you (JDRamirez) said, to find a framing and position that declutters the image to the greatest extent possible. That can be hard indoors. But not impossible. The first thing to try is to shoot from low to high. Generally that clears out the trackside crowd, excess hurdles, and the other riff-raff present in his shot.
Also, shooting into the corner from that position, across the track, puts the potential background much closer to the athlete, making shallow DOF much less effective. Shooting from even another 30-40 meters down the track would have at least equalized the distance between the shooter to athletes and athletes to background. Combine that with a 2.8 aperture and the separation would be much more effective. Better yet, for an indoor arena, the 135 f/2 really shines here to drop out backgrounds in favor of the athletes. The guys with the 200 f/2s are really in business, though can be challenged for working space in the small venue, when trying to get uncluttered angles.
My personal style for this stuff is shooting low to high. It's not exclusive, but it's certainly the bulk of how I tend to shoot. I like to get the athlete taller than the horizon in the background. As I said above, it's about making them a superhero. Everyone wants to feel and look great when they are making such physical efforts.
I contrast my approach to the approach of the event company that shot the 1/2 marathon I ran recently. They had a beautiful shot venue where we were running alonside a river, with palm trees and an ampitheater. How did they shoot the shot? Looking down on us from ladders. I look like I have a bush growing out of my head. The photo looks ok, but barely. I noticed they were using equipment like 7Ds and 70-200 zooms. They could have done so much better with the shots. I just wanted to scream "Make me a superhero!" But I don't imagine the shooters would have understood. They had their ladders and their planned shot. It cleaned up their backgrounds for them...by making it mostly the sidewalk behind us runners. Blah. Boring. No water in the shot, no ampitheater. No context. Runner with a bit of grass and sidewalk. It could have been taken anywhere.
On the track, if you must clutter the background due to positional limitations, try to use the scoreboard in the background. At least then the viewer has a sense of context to the shot.
