Is it possible to do a controlled demolition to a building in just a few hours time?

It could have been irreparably damaged and they just decided to let it go. Still, it always seemed strange to me. Considering how massive the cleanup effort was already going to be, why add to that and knock down another decent-sized building. Also, its clear that people weren't warned. I remember watching live footage of 9/11 when Building 7 went down, the reporter was interviewing this lady carrying her baby, and when the building went down they were just covered in smoke, both the mother and the reporter were crouched down, trying to protect the baby.