Trevor was planning to be the last to descend, is Kurt going to spoil that plan? If so, then Trev will precede only Kurt, thinking that he can probably make the climb using just his skill, but, relying on the rope just to be safe.
While the altar is obvously the focal point of this room, Trevor is concerned that in giving all of their attention to this feature, they miss something else that should be rather obvious. He peers all around the room looking for ... well, basically anything.