Watched this fall in today's 1500 a few times and my takeaways are (1) Ahmed is mostly at fault for his own fall (flailing arms all over the place), (2) Ahmed spitefully dragged Avila down, and (3) Ahmed is a pr!ck based on #2 and based on his interaction with Avila afterwards.
Don't know if the video will stay posted but it's on youtube now and link is below. Watched it a few times in slow-motion. Ahmed bounced around like a pinball at first but actually righted himself. When he gets out of control again, you can clearly see him drag Avila down. At first he may have grabbed Avila out of instinct, but he held Avila's jersey the entire way down and never let go until it was too late for Avila. When runners passed them 2 laps later, you could see Avila try to slap hands with him as a conciliatory gesture and Ahmed dissed him.
It's too bad there's no more consequence to this than not getting to race. Based on pulling Avila down, I think he should be suspended for a meet or two (were such a consequence be possible).
LRC Note. We have made a video of the fall - first at regular speed and then slow mo.