These people are here, in the city. I've seen them in Brooklyn on Atlantic Avenue. I don't think they can hijack another plane, but there is so much more they can do. And you can't watch everyone. There is absolutely zero security on the subways.
Someone can do something on the subways at any time and nothing can be done about it.
I went out and bought batteries for my flashlight and a candle tonight. Just in case. I have nearly broken down in tears a few times. Heartbreaking stories about people in the buildings knowing they were going to die and making last minute phone calls or sending e-mails saying goodbye to their loved ones. I don't even care who did this anymore.