Explosion before the destruction of building 7

Explosion before the destruction of building 7.

An explosion is clearly heard before building 7 is destroyed.
This video is part of NIST'S recent FOIA release.
Download and compare the videos yourself
The video above with the explosion is found below:
http://911datasets.org/images/Interna...

The same but longer video mysteriously without an explosion is found below:
http://911datasets.org/images/Interna...

http://www.youtube.com/watch?v=qdFdo9kVPvM