There is a part of Effy that doesn't quite believe it, but fortunately it is also a part easily silenced by too much energy and not enough sleep, by all the drugs and drinking and no food or water in her stomach to dilute it all. As little faith as she has in herself, she doesn't manage to hold onto to the thought for long, and it vanishes in the next instant, forgotten when the train jerks once again and she latches onto the nearest whatever. It's Harry's hand, the one not on her hip, and for whatever reason, that makes her laugh.