In the graphic used to show the demolition of the building. Windows are shown being blown out of their panes. Demolition companies never leave glass in windows when blowing up a building. In fact they usually remove not just the glass. They remove the panes, the jambs, the sash and the sills. They make every effort to reduce debris being blown out and potentially injuring someone.
It is not legal to implode a building within the NYC limits. It must be dismantled.
Barney and Robin track Ted down from a voice mail that Ted left on Lily's phone. Ted's voice mail was left while he was on the subway on his way to meet up with Zoey, but Barney and Robin have Ted's phone as he forgot it before he left at the bar.