If one of the bad guys made Amy drive to the bank, that may explain the reports of erratic driving. She may have been trying to attract attention or maybe get pulled over. I know I was lost one time in a VERY BAD area of an unfamiliar town when I was traveling for my job years ago. I didn't even feel safe asking anyone for directions, and this was before the use of smartphones or Garmin devices.
So I started running red lights like crazy, and accelerating from a stop as fast as I could. Alas, no police appeared...where are they when you need them?
In this scenario, it is likely that there were more bad guys at the house, guarding the other hostage(s). I guess the thing to do if we were in that situation is to crash the car hard on the perp's side, hitting a pole or something. But I guess there would be a risk that you wouldn't be in the sort of shape to tell the officers what is going on....maybe the plan back at the house was to start ending lives if they didn't come back from the bank run within a certain period of time.
Just speculating...