NBC News chief foreign correspondent Richard Engel on Americans wanting to leave Afghanistan: "There's no possible way at this stage that the U.S. is going to get everyone out who wants to leave or who may have changed their mind and decided that they now want to go and don't want to ride it out with the Taliban." "We're in the final hours now," Engel told MSNBC host Andrea Mitchell on Monday. "There is quite a bit of activity over in Kabul, according to witnesses, with drones and fighter jets in the air. The smaller the footprint gets, the more dangerous it is, and ISIS has made it clear that it wants to get its parting shot." "ISIS was not really a major factor in the war in Afghanistan," he said. "It arrived late to the battle and it was always a secondary threat. ISIS carried out some spectacular -- I hate that word -- spectacular attacks, high profile attacks, some gruesome, disgusting attacks killing many civilians, including on hospitals and wedding halls. But they never had a ground force like the Taliban. And now ISIS is trying to go for the historical record and get a parting shot against the Americans so that it can redeem its terrible name and say that it was responsible for helping to drive out or responsible for driving out U.S. troops."