In this episode, James shows some special footage of the towers taken from Hoboken across the Hudson river, which demonstrates that the white smoke rising up from the base of each tower just before each tower falls is a clear indication that they were cutting all of the core columns at the base of the tower so the remaining bombs the basement or so odd core columns that remain standing after the tower is obliterated.
The second part talks about the BathTub of the WTC, and how it was built and what it was meant for.
No micro nukes were used below the 50th floor, instead they cut the columns at the base, In this way they did not disturb the bathtub.