Why would they want to transport her to CPMC?

Because it has the best NICU (Neonatal Intensive Care Unit) on the West Coast, and is prepared to deal with preterm newborns at a very young gestational age.  Frankly, 32.5 weeks is not a terribly underdeveloped stage given today's technology, but anyone born before 35 weeks can have medical issues that outstrip the care capabilities of many hospitals.  CPMC would be the safest place to have a delivery before 35 weeks, so that's where they wanted us to go.  Anyway, don't interrupt.

When I got to Peninsula at 11:39 or so, Mom was with Ginger (she had driven her to this appointment).  The nurses were prepping her for the ambulance to CPMC, but the ambulance team was still enroute.  We were told it might be and hour and a half for them to even get there.  Okay, we can all breathe a little.  The contractions were frequent but still fairly mild, so there was a chance to get them under control -- maybe even stop them.  Ginger was already on nifedipine to inhibit the contractions, so it looked like we might be going to CPMC to get them further under control.  The fact that its NICU is so advanced was just going to be an insurance policy against the failure of Plan A.

Because we had time and it looked like we might be in for a long hospital stay for bedrest, I suggested I would drive home to gather some things.  I told Ginger I'd be back.