Ed Harbert is going to find himself working in the E.R. (or otherwise getting his hands bloody) at some point.
made a point of establishing that he has experience as an E.R. doctor and
still has a valid M.D. (meaning he's keeping up with the continuing education and, at least, the minimum number of hours of practice required to maintain a current license). They wouldn't have given him the gun if they didn't intend to have him fire it, would they?
Pineda transferred to a different hospital to finish her residency.
Sometime between the end of Season 2 and the beginning of Season 3, Pineda seemingly leaves. Considering how dedicated she seemed to being a doctor, her leaving before the final year of residency seems unlikely, unless she transferred hospitals. Looking at everything that has happened to Pineda at Angels, from her ex girlfriend coming back (an ex she met at Angels no less), to said ex girlfriend dying, to being stalked, stabbed, and almost raped by a patient (and said patient also killed a different doctor). And that was all in Season 1. In Season 2, shes put on leave for keeping Guthries Parkinsons a secret and once she comes back, she nearly dies from getting infected with an unknown illness. Pineda very well could have transferred hospitals because so many bad things have happened to her at Angels.