For context, Booker didn’t exactly play a major role in this episode because it primarily focused on Captain Burnham and Tilly trying to solve the latest mystery in the Progenitor puzzle. However, Booker does have an interesting interaction early on with Dr. Culber in which the medical professional tells the former courier he needs to find a way to relax.
After all, there is literally nothing he can do in the search for the renegade lovers Moll and L’ak. The doctor’s advice is for Booker to find some kind of distraction that will help to recharge his mind so when Discovery really does need him, he will be ready.