"Controlled demolitions take weeks of planning" because under normal circumstances, the risk of waiting is not that high. That doesn't mean that subject matter experts aren't capable of making an intelligent plan in a short period when a building is catastrophically damaged in heavily populated area where waiting can very easily result in more damage and more risk of casualties.

As for "melting iron", if you're talking eyewitnesses before the demolition, they have no idea what was melted. If you're talking after, no shit they used demolition-grade explosives. It was a fucking skyscraper in the middle of a massively populated city that wasn't stable. It had to come down.