On the roof they encountered a major crisis, though Smith was not aware of it.  He was undergoing the keen delight of seeing sky; he had not seen sky since the sky of Mars.  This sky was bright and colorful and joyful - it being a typical overcast Washington grey day.  In the meantime Jill was looking around helplessly for a taxi.  The roof was almost deserted, something she had counted on, since most of the nurses who came off duty when she did were already headed home fifteen minutes ago and the afternoon visitors were gone.  But the taxis were, of course, gone too.  She did not dare risk an air bus, even though one which went her way would be along in a few minutes.