So, the cop with the dog was in on it, and most likely were the ones that decided to fix the metal detector as an excuse for him to pass freely. But there were 3 cops at the wall, and two of them fell and retreated to the door the shooter came out of. So those 2 most likely were in shock or scared for their lives and fled.
We have to get to the bottom of this, because if insider authorities are targeting Trump, then eventually, something might get through.