Why in the hell does an unmanned vehicle need to stay a quarter of a mile away? Are they imploding it, or EXploding it? You really want to get that shot from around 500 feet. If building implosions aren't an ideal subject for a quad, I don't know what is.
I hope you're getting some footage of the building before they demolish it, and try to get some from the exact position and altitude you intend to get the explosion from. When they are ready to detonate, a lot of things will look different even before the blast.