If he is going into a shed, I have found, that sheds can cause a boa to stress more. My guy is usually fine, but when his eyes cloud up for a shed, he seems justifiably more defensive. Shedding is a very vulnerable time for snakes in the wild.. and sice boas are more sight-oriented than, say, a BP with its heat pits.. the cloudiness in the eyes could make him freak out more..