There was no reason to think WTC 7 would collapse. The debris damage was actually insignificant.
NCSTAR 1A pg 55 [pdf pg 97]
The initial westward progression and the overall speed of the collapse was not sensitive to the extent of the estimated structural damage to WTC 7 due to the debris from the collapse of WTC 1. When the global collapse was nearly complete, there was some small sensitivity to the extent of the initial damage in the southwest portion of the building.
The normal office fires were far less severe than other high rise fires.
They knew it was going to be imploded.
http://www.youtube.com/watch?v=rY6rSLXSsdc
An explosion can be heard in the video above and this one [at 0.11]
It helps to turn up the volume [and the bass if you can].
The camera was ~2,250 feet away = 2 second delay.
http://www.youtube.com/watch?v=XrnmbUDeHus&feature=player_embedded
You will now quote from the deniers playbook:
1) Other things make loud noises.
2) Explosion does not necessarily mean explosives.
You will never admit that those sounds could have been explosives because you are in denial. You will insist that there is no way they could be explosives and than claim there were no sounds of explosives. If nothing else, y'all are very consistent.