@2:08 of this Pentagon 9/11 video, a very strange phenomenon occurs

Pay close attention to the first 20-25 seconds. This event is approximately 8-10 minutes after impact detonation.

A thick plume of rapidly ejected white smoke means what? ( incendiary device )

What building materials could possibly cause this phenomenon? ( none )

Look at man near triage blanket in foreground. Why is he worried ( hands to head ), why does reverse direction twice, and then hesitate before proceeding?