Just played a doctor from level 1-10. Kinda sped through so I could have missed some stuff. There are a few different types of "work" that can happen during business hours. I got my first one at level four, and maybe three out of five days after that I had the special opportunities. I never had a random opportunity to save someone from choking but I didn't really eat out, either. Oh, some of the special opportunities did lower the performance meter (even though it counted as Working) but either came back up when the job was completed or when my sim went back to work. But others had the performance bar go up the whole time, so I don't know what that's about. You can work "overtime" if you have a couple opportunities on the same day, this happened for me during a "patch job." My sim patched up the criminals and then went to patch up the police officers.
I do like the new additions to the medical career. I believe there are some new "regular" opportunities as well, the kind with more than one step (that is, talk to x person, talk to y person, investigate the City Hall, talk to y person again, convince 5 sims to vote, etc). Also you can do experimental treatments on yourself or others (was only successful for me with a good friend or better), I believe once every 24 hours. You get a small bonus and a boost to your performance meter. The relationship with the sim you experimented on can go up or down depending on what the effect was.
Also you can use your phone to Follow Up With Patient, either by talking to them on the phone or by going to their house (making a house call). On the phone gives a performance boost but if you go to their house, you earn some money as well for Giving Follow Up Exam.
It's really kind of difficult to not get promoted every day.