She calls it an "impossible cosmic joke" that she's still stuck here, and Peter tries to pretend that he knows exactly what she's going through, which is awfully presumptuous of him. "But believe me, Dana, this is not the solution." After a moment Dana says she guesses they'll find out soon enough, and Peter hangs up. Peter asks the FBI tech if they were able to trace it, and he shakes his head. Hey, try calling back with the Caller ID identifying you as one of her dead children! Maybe that will work! Due to the magic of sound enhancement, though, the FBI team pick out the "Next stop, Norwood station" in the background. There are three possible trains that could apply this time of night, though; however, once Bell and Walter find out the time Peter spoke to Dana, they get to work calculating which train it would be, working and discussing it at the same time. Peter, hearing it on his end, asks Astrid what's going on, and she says that they're doing "that thing where they don't finish their sentences." Hee! They arrive to the same conclusion at the same time: She's on the 6:25.
Meanwhile, on the 6:25, buddy across the aisle from Dana asks her to keep an eye on his stuff while he goes to the bathroom. Apparently he takes her tortured expression as a yes, because off he goes. Just moments later, the train grinds to a halt with metallic screeching as police and FBI pull up, lights flashing and sirens blaring. Broyles tells the... conductor? Ticket-taker?... that there may be an explosive on the train, which they think is due to go off in about eight minutes. Broyles shows him a picture of Dana, and the dude kind of hilariously says, "There are over three hundred people on this train!" Yeah, no shit? IS SHE ONE OF THEM? SHE HAS A BOMB, SO MAYBE YOU COULD AT LEAST THINK ABOUT IT. Seriously, it's not exactly a needle-in-a-haystack thing, illustrated nicely by the fact that bathroom buddy happens by at that moment and is able to say, "She's in the next car."