Arkain can hear what Crescent is saying to the others but he can't hear all of what the others are saying in response. He clearly hears Crescent say about someone trying to kill him. He yells up.  "Hey, Wait a minute. What the heck do you think you are doing? We have something to say in this. We are still alive down here. I have no interesting in being killed nor do I want you to kill Crescent. There is more to Crescent then you know."  He looks over at David. "I need your help to try to communicate with some crazy person up there that wants to kill Crescent. We can't let him do that. I want to see Nibita again."