Pat Busovicki’s Eastern Caribbean cruise on the Carnival Dream almost ended in a nightmare. One afternoon, after plummeting down its Twister water slide, she says, she found herself trapped in a dangerous undertow. “I couldn’t get out,” remembers the retired librarian from Westlake, Ohio. She says that crew members didn’t assist her, and only after her sister cried for help did another passenger jump into the water and rescue her.