This is indeed what took place. This hapless individual was manipulated through mind control to stand down, in effect, and further compound the problem by warning others away from the building when their presence was sorely needed to overwhelm the school shooter and stop the carnage in process. As you know, this is standard operating procedure for all tragedies of this kind, that the orchestration goes beyond the perpetrator to others in the vicinity, and especially to first responders—to make them complacent, to cause delays, to create confusion so they work at cross-purposes, or not carry out a useful role at all thinking their help is no longer needed and someone else is taking care of it, and so forth. There are many ways to make this happen by controlling those who give the orders in particular.
In this case, this school protection officer was tasked to take it upon himself to direct first responders at the scene and, in a state of confusion themselves, acceded to someone seemingly in charge and this further contributed to the death toll on that tragic day. This is not the fault of the individual—it is very much the case he is as much a victim as others who were a witness to the tragedy or affected in some way. All of humanity suffers when such things happen.