My first thought was actually that the 2 prophets had arrived for the Watchtower, meaning it would collapse itself in the not to distant future.
Secondly I thought the watchtower would say the twin towers are the final prophets for the coming armageddon. I'm not aware of any official communications on behalf of the wtbts regarding the subject, are there? In fact i did stay in New York in 2000 but I only walked brooklyn bridge halfway, never made it to brooklyn. My question; did brooklyn HQ have a direct view of sept. 11th? If so, they should now know how sick they really are, prophesizing sept. 11th on the whole world.
If it's up to me to prophesize about sept. 11th, I'd say what i thought first, and that's that. The Watchtower will burn bottom up.
Bas