Interesting video. Another option for UAV operators might be to move the UAV closer to an obstacle (building, antenna, tree, etc.) than a rotor disc can get. That could be a faster path to safety than landing from 400 feet AGL. Indeed, in the case of news or public service (police) UAV observation operations, intentionally positioning a UAV in proximity to an obstacle like that would automatically deconflict UAV/helicopter operations.