Timmy,
First off thanks for sharing this call with everyone, also don't beat yourself up too much about it. Here is my take on scene control.
In the crowd find someone you think can help calm everyone down. Sometimes you can find someone that the crowd / family / etc... can relate to and they may listen to them before thye listen to you. This has helped me on a few scenes over the years.
Remember "scene control" means many different things and each situation is different. Often the tough guy Cop approch only pisses people off more and makes the situation that much more intense and stressful.
Anything else I say will just be repeating what's been said already. Again, don't beat yourself up, learn from it and move on. Some day when you are a crusty seasoned medic you can tell your rookie this story.
