The video "proves" the same thing we preach on here all the time :
Training and
Practice are crucial tools.
But, the exercise was a bit rigged, the BG's
knew there was an armed student, and, who he was. I don't think the hoods disguise the students to the point that a trained officer could not pick out the armed target and neutralize him before he could deploy the weapon.
The other thing the video "proved" is that a TV production can be biased to show whatever results you wish to portray, go figure