"Ms. Weaver says it was the reinvention of the Ripley character -- this spirit of nihilism, as she calls it -- that persuaded her to do a fourth Alien film after she had all but decided that three were enough. "It seemed a challenge," she says. "You know, we all feel that when things get too difficult we have a way out, that it's finally up to each of us, that we can exit. And I thought, how awful it would be to find yourself in a world where you had exited, with all sincerity, and they had brought you back against your will. I tried to go with that idea as far as I could.""