Complex sentence: As Elizabeth screams, Nick and Phibes rush back into the autopsy room, where they see the corpse lifeless again on the floor, it appears to have scratched the number "3" into the floor with a scalpel.
Split into simpler sentences: As Elizabeth screams, Nick and Phibes rush back into the autopsy room, where they see the corpse lifeless again on the floor. However, it appears to have scratched the number "3" into the floor with a scalpel.