"I am part of the Security team." She thought it was an appropriate placement. "Logan is on with me as well." Where else would you put two mutants that had been engineered to be used as weapons? Though she had been conditioned to the point that it was a little difficult for her to make her own choices over the things she was told to do.
As he didn't question her verbally, she did not explain. She simply assumed, if he was to know, Lorna would inform him. Or time would progress and it would become obvious to the rest of the world as well.