Rosalind was exhausted. She didn't know how to keep skirting around these sorts of questions. She didn't know if the stupid nylon was going to work. She didn't know if she was ever going to be able to go home, let alone save her mother's life.
She didn't know anything and she hated it. Her father wasn't the only one who hated not having all the information about everything.
She had done her best not to tell him about the time machine because she was afraid his mad scientist tendencies would take over. He had damaged her trust in him with what happened the day they got sent back in time. At one point, he would have been the first person she went to when she had a problem but she had learned he was rather unreliable.