In the area I work in (metro N. Calif), the standard is an engine company and medic ambulance (FD or private) on every code 3 medical call. The reasoning for this is: 1) There are more engine companies spread out, so they will usually arrive first and can perform immediate treatment and assessment. 2) Running a stat call with just one other person, even if they are a medic, can be hectic and inefficient. We almost always have a two or three-person engine company, so one person can get vital signs for us (and do other things like set up an IV bag or get oxygen going) and one or two can get the gurney or stair chair. That leaves the medics to assess and treat the patient and perform proper documentation (good field notes). In E!, the squad had two ambulance attendants (gurney jockeys) on the call to help with patient transfer.