Many are critical of that guy. If you're that officer and clime up a ladder to the edge of the roof and get a rifle pointed in your face what are you to do. He could have proved he wasn't "in on it" by taking it in the head? The roof top is a very defensible position.

The failure was letting the shooter up there in the first place. The security forces were in a really bad situation to try and get him down with the roof pitch so shallow and the building so tall.

Who gave the orders that left the building unsecured and who did not immediately pull Trump when that LEO and the crowd confirmed there was a shooter? Who, listening to the radio chatter was responsible to make the call to pull Trump and shut everything down? That person is more suspicious than the local cops.