Looking at you anxiously, his eyes shifting about to see if there was anyone around, Chitin answered "This order supersedes anything you have of me, for it comes from Queen Chrysalis herself." Well, that would certainly explain why he was apparently scared. Given he seemed almost ignorant of her commands before, you were guessing some crazy hive mind bullshit just happened a moment ago, and that's why he became a statue. "There are intruders in the hive and Queen Chrysalis gave two very specific instructions. To find and detain the intruders immediately and, more importantly, bring you to the safety of the throne room," Chitin elaborated.