Perfectly reasonable and lawful self defense but guess who goes to Jail?

This is a farily long video but definitely worth the time to watch.

2 young couples assaulted in a parking lot after leaving the bar. One of the young men steps up and disarms the gunman but he ends up in jail.

I always stress in classes that you can be 100% innocent and correct in your actions and still end up facing felony charges just like this young man.