New York: When the first plane struck 1 World Trade Center at 8:48 am on Tuesday, the people in 2 World Trade Center who saw the instant   damage to the other tower realized clearly what they, too, must do: get out fast. Katherine Ilachinsiki, who had been knocked off her chair by the blast  of heat exploding from the neighboring tower, was one of those. Despite her 70 years of age, Mrs Ilachinsiki, an architect working on the 91 floor of 2 World Trade Center, the south tower, went for the stairs. Twelve floors above her, Judy Wein, an executive  , cried sharply and set off too. But others up and down the 110 floors, many without seeing the damage across the way and thus unclear about what was happening, were not so sure. And the 18 minutes before the next plane would hit were ticking off. Most people had no idea about what was the best thing to do, formal announcements inside the south tower asked people to , assuring them that the building was sound and the threat was limited to the other tower. Some left, others stayed. Some began to climb down and, when met with more announcements and other cautions   to stop or return, went back up. The decisions made in those instants proved to be of great importance, because many who chose to stay were killed completely when the second plane crashed into the south tower. One of those caught in indecision   was the executive at Fuji Bank USA. Richard Jacobs of Fuji Bank left the 79 floor with the other office workers, but on the 48 floor they heard the announcement that the situation was under control. Several got in the lifts and went back up, two minutes or so before the plane crashed into their floor. "I just don't know what happened to them," Mr Jacobs said. From the passage, we know that the south tower was hit by the plane    _   .
at 8:30 18 minutes earlier than the north tower at around 9:06 at 8:48