As J'onn J'onzz is calling off names of Justice Leaguers to go to the transport pad, they leave after he's called their name. After he calls Fire and Ice, he calls Dr. Light. But Dr. Light turns to go to the transport pad before J'onn has called her name.
When Booster arrives at the subway and watches the various items getting sucked down below, the sign above the stairwell reads "Metro". When Dr Simmons gets caught in the flow and Booster prevents her from entering the black hole, the sign changes to read "Down Town" with the addition of an arrow.
Why would Dr. Daniel think it was a good idea to go into the city from his secluded lab, if he wants to keep people safe from the black hole.? That's just making the very situation he's trying to avoid.