Thanks for the link to your post @thoughts-in-time . Yes, there always seem to be a drill that mirrors the situation going on at the time these events occur. I simply try to capture some of the evidence that doesn't fit the official narrative in order to help figure out what really happened. It reminds me of the San Bernardino event where there were multiple witnesses also stating there were multiple shooters. Proof of such is here:

The video above features CBS reporter Scott Pelly talking with an eyewitness. Note he tries to correct her story at the end of the segment.

The witness in the video above states "We hear shots and as we look out the window a second set of shots goes off....(emulates sound of automatic gunfire) and we saw a man fall to the floor and we just looked then we saw three men dressed in all black military attire with vests on holding assault rifles and they opened up the doors to building three, and one of them opens up the door to building three and he starts to shoot all over to the room, that's the room that we typically have conferences and we just heard more gunshots go off".

Local NBC station interview with witness who states " I saw three white men in military fatigues, um....taking off"

I have the contradictory witness statements from the Parkland high school up on my page today for other interested viewers.

Links: SECOND STUDENT WITNESS SAYS UP TO THREE SHOOTERS IN PARKLAND FLORIDA SCHOOL MASS SHOOTING

https://steemit.com/news/@clarityofsignal/3fog4wv2

Multiple Shooters Participated in Florida School Shooting According to Eyewitness Alexa Miednik

https://steemit.com/news/@clarityofsignal/ixl3sp2w

I note also in the video you have posted @thoughts-in-time that the school teacher witness states "I didn't notice because he had a mask on". That's interesting as well.