Tourists of the Apocalypse

All of the characters have questionable morals. There is no one to call a hero or even a good example. There are a couple of minor plot points that bug me:

1. If Lucy worked there for years, why would anyone be surprised at her disability when she entered the building?

2. I find it hard to believe that Dillon could launch the 500 pound gun to land on the hood of the following car. Our seems to me that would take more power than one man could exert.