The fact that some of the BP drugs inhibit the 'fight or flight' response, is not in my mind nescessarily a bad thing.
The response is there so we can either belt a sabre tooth tiger over the head, or run away from it and would do little to provide a reasoned rational response to an underwater crisis.
What the 'f or f' response is likely to do is; close down your peripheral circulation (not good for off gassing), make you purge your stomach contents (into your reg), and empty your bowels (which with either a wet suit OR dry suit is not something I would relish).
Maybe we should ALL be on beta-blockers when we dive
