explosive devices. now that this has gone from a chaos outside the airport to a catastrophe outside the airport, there are difficult decisions to make, but decisions crucial ones that will effect how the next 100 hours plays out from a u.s. perspective. >> trying to figure out how to extricate the remaining americans at the very least who want to leave, that's a complicated task now. >> comply cayed, i would say, is an understatement here. if it's unsafe to move them on the ground, be it by simply having them walk or simply by having them take a car, you don't have another option other than helicopters. there have been limited helicopter operations into kabul to bring out americans and bring them to the airport. but those have been of short distance and krduration. meaning the americans were close to the airport. that brings its own element of risk, especially now that it's clear isis-k is ready and waiting and trying to carry out attacks against u.s. forces and