People who believe that the WTC7 was a controlled demolition really have no idea what a 'controlled demolition' is. Firstly, it's a controlled 'implosion' although the building is usually demolished in the process. What the 'implosion' means is that the building implodes into itself. Buildings which fall in one direction or another instead of straight down are 'controlled demolitions'.
Here's an example of a controlled implosion:
Here is a controlled demolition:
In either a demolition or an implosion, there are months and sometimes years of planning, then months of preparation which includes the demolition of support walls and, for steel supports, removal of the outer 'decoration' right down to the bare steel. Special charges are then attached strategically to the bare supports. When set off, these charges actually melt through the supports in an explosive charge. They don't actually blow them up.
If the WTC7 was a controlled implosion, along with the Twin Towers, there isn't a person in New York City who wouldn't have known about it months ahead of time, and they certainly couldn't have thrown it together in a few hours as some theorists have claimed.
If you watch the original video above again, watch the right-hand side of the building. You will see dark 'spaces' appear. A lot has been made of these as proof that it was a planned and controlled event. When you watch it and see the spaces appear, back it up again and watch more carefully when those spaces appear. The building is already collapsing at the bottom. The spaces appear because of the collapse. They had nothing to do with causing it.