So I was playing a new character and I talked to House for the first time, went back into the Casino floor, but in a glitch i was suddenly talked to a heavily scarred girl with metal stuff attached to her and she was named "Kate". She said something about Nellis and me rescuing her. She talks slowly and awkardly, almost like she is shaking while doing so. There was also some mention of a "factory" and a quest called "The Dead Factory."
Where the hell does she come from?

Did you download the Beyond Boulder Dome Mod because she is in it.

I think that may be it. I did download it. Thanks. I will just disable it for now.