Soon after the second WTC tower is hit, a senior Secret Service agent who is responsible for coordinating the president’s movements establishes an open line with his counterpart at the FAA. This FAA official tells him of further planes, on top of the two that have already crashed, that are unaccounted for and possibly hijacked. Although the Secret Service agent asks someone to pass this information on to the Secret Service’s operations center, the 9/11 Commission says that either this does not happen or else the message is passed on but not disseminated. Therefore the information fails to reach agents assigned to the vice president and, consequently, “the Vice President was not evacuated at that time.”
[9/11 Commission, 7/24/2004, pp. 464] However, some other accounts contradict this, saying the vice president is indeed evacuated from his White House office by Secret Service agents at around this time. [New York Times, 9/16/2001; Daily Telegraph, 12/16/2001; ABC News, 9/14/2002]