Unfortunately there is really no way to prepare for clinical questions - you either know it or you'd have to look it up (...just like in practice, right?). In my opinion, they aren't looking for clinical accuracy as much as they are trying to figure out your thought process and how you think on your feet. You'll be fine if you brush up on general interviewing skills and come up with some responses to give in the event you don't know the answer to a clinical question.
At the hospital that I got hired at, I had 2 separate panel interviews (2 months apart) and a phone interview (with 2 people). I think it was a bit overkill and they did that just because I was a new grad. But like any other interview, most questions were scenario based. The hardest were the ones i bet they added in there for 'fun' like what was your fav therapeutic subject in school and why, what drug would you be and why, etc.
Good luck!