Complex sentence: She appears to die before reanimating as a ravenous zombie and kills the attending nurse, who also returns as a zombie, before Lionel locks them in the basement and keeps them sedated with animal tranquilisers.
Split into simpler sentences: She appears to die before reanimating as a ravenous zombie. She kills the attending nurse, who also returns as a zombie, before Lionel locks them in the basement and keeps them sedated with animal tranquilisers.