What does Cassia feel about her father's destruction of Grandfather's tissue samples?

On her way home home, her father comments that someone stated they saw someone who looked like her at the site. She explains why she was there. He looks a bit disappointed when he finds out what she did, but he tells her she did the right thing. He explains that Grandfather asked him to destroy his tissue samples. This is hard for Cassia to relate to. She understands her father's position but can't decide whether or not he was right to listen to Grandfather's request when the results are so final.