Good luck with the move and as I did somethign similar let me share some experiences...
(1) DON'T EVER give the impression you are deperate for the job. Don't ever feel afraid you will get fired or shown the door. Believe me they never need a reason to do that. So just get on and focus on your work.
(2) DON'T be afraid to ask anything even if you think it is silly or elementary or you think you can find out later. Just ask the question (but ofcourse don't ask really silly ones) and make them sound intelligent and probing.
(3) Get thick skinned - if your boss or colleague say your work is not up to scratch, give them a mental two fingers and move on. Just improve it for the next time.
(4) Never do later what you could have done yesterday.
(5) Communicate always all the time with everyone. Especially when you are on a client project. Consultants rarely come up with anything new or innovative. They only dress up a previous assignments differently. Someone out there has the knowledge or the solution. So why should you re-invent the wheel. Your firm would not want you to do that - simply deliver the goods on time.
(6) Don't expect anything seriosuly challenging other than how to stay awake long nights.
I can go on and on but the bottom line is this - you will pick up the important elements of the consultancy work with time but none of the MBAs will ever master your research and medical background ever so clearly you can see who is superior in this game. Just make sure you don't shy from showing it.
Good luck. May I ask where you are joining?