Teacher:In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.
Teacher: Now, understand the problem? Solve this instance: Passage: Two days after the events of the first film, a traumatized and blood-covered Sarah escapes the cave with no memory of the events. She is taken to a hospital, where it is found that some of the blood on her belongs to Juno Kaplan. Sheriff Vaines takes his deputy Elen Rios, Sarah, and three spelunking specialists – Dan, Greg, and Cath – to the cave to find the missing women. The team members are sent down via an old mine shaft operated by the old, mysterious Ed Oswald.
The group discovers Rebecca's mutilated body, causing Sarah to have flashbacks of the crawlers and causing Vaines to believe Sarah may be responsible for the girls' disappearance.  While crawling through a tunnel, she attacks Vaines and the others, causing the others to split up. Vaines runs to search for Sarah, and in the process is surprised by a crawler, and fires his gun in a panic, causing a minor collapse in the cavern which traps Cath, separating her from Rios, Dan, and Greg.  The three decide to find an alternate way around in order to try to free Cath and arrive in a room full of bones, where they find Holly's video camera. They watch it and realize the women were attacked by the crawlers. The three are then themselves attacked by crawlers and separated.
Rios starts calling for help, alerting the crawlers to her location, but is rescued by Sarah.  The two then watch as a crawler kills Dan and drags his body away, prompting Sarah to inform Rios that the crawlers are blind and hunt via sound. After escaping from and killing a crawler, Cath finds Greg before the two escape from another crawler and find Sam's body. They decide to try to use her to swing across a chasm, but are attacked again. Greg sacrifices himself to buy time for Cath, but she ultimately does not survive.
Student:
Who attacks someone, causing the group to split up?